1 Mathematics Review Notes for Parents and Students Grade 8 Mathematics 2nd Nine Weeks, 2013-2014 Julie A. Byrd, Suffolk Public Schools Updated 10/13 2 Content Review: Standards of Learning in Detail Grade 8 Mathematics: Second Nine Weeks 2013-2014 This resource is intended to be a guide for parents and students to improve content knowledge and understanding. The information below is detailed information about the Standards of Learning taught during the 2nd grading period and comes from the Mathematics Standards of Learning Curriculum Framework, Grade 8 issued by the Virginia Department of Education. The Curriculum Framework in its entirety can be found at the following website: http://www.doe.virginia.gov/testing/sol/frameworks/mathematics_framewks/2009/fr amewk_math8.pdf SOL 8.10 The student will (a) verify the Pythagorean Theorem; and (b) apply the Pythagorean Theorem. In a right triangle, the square of the length of the hypotenuse equals the sum of the squares of the legs (altitude and base). This relationship is known as the Pythagorean Theorem: a 2 + b 2 = c 2. This is the Pythagorean Theorem formula. This is the hypotenuse. This is the altitude. This is the base. Julie A. Byrd, Suffolk Public Schools Updated 10/13 3 This is another illustration and way of visualizing the Pythagorean Theorem. Example: Find the length of the hypotenuse (side c). OR 4 cm 3 cm The length of the hypotenuse is 5 cm. The Pythagorean Theorem is used to find the measure of any one of the three sides of a right triangle if the measures of the other two sides are known. Whole number triples that are the measures of the sides of right triangles, such as (3,4,5), (6,8,10), (9,12,15), and (5,12,13), are commonly known as Pythagorean triples. Julie A. Byrd, Suffolk Public Schools Updated 10/13 4 SOL Practice Items provided by the VDOE, http://www.doe.virginia.gov/testing/sol/stand ards_docs/mathematics/index.shtml 4. Which of the following equations is represented by the figure? Answers are located on the last page of the booklet. Pythagorean Theorem, SOL 8.10 1. Which group of three side lengths could form a right triangle? 2. Mr. Malone plans to construct a walkway through his rectangular garden, as shown in the drawing. 5. What is the value of m in the right triangle shown? 3. Three triangles are drawn in rectangle PQRS. 6. The legs of a right triangle measure 9 inches and 12 inches. What is the length of the hypotenuse of this triangle? Julie A. Byrd, Suffolk Public Schools Updated 10/13 5 7. Which correctly names the hypotenuse of the triangle pictured? 10. What is the measure of 8. Which names one of the legs of the triangle pictured? 11. Triangle CAT was in Cedric’s mathematics book. ? 9. A waterslide is one side of a right triangle as shown. 12. Julie A. Byrd, Suffolk Public Schools Updated 10/13 Dale drew triangle DOG with the following measurements. 6 SOL 8.11 The student will solve practical area and perimeter problems involving composite plane figures. A polygon is a simple, closed plane figure with sides that are line segments. Below are examples of different polyhedrons The perimeter of a polygon is the distance around the figure. The perimeter of this figure can be found by adding all five sides together. 1 + 5 + 4 + 2 + 7 = 19 P = 19 units The area of a rectangle is computed by multiplying the lengths of two adjacent sides ( A lw ). Example: Mr. Jones has a rectangular flower garden. What is the area of his garden if the length is 7 ft and the width is 9 ft? A = lw l = 7 ft, w = 9 ft A = (7)(9) A = 63 ft² Julie A. Byrd, Suffolk Public Schools Updated 10/13 7 The area of a triangle is computed by multiplying the measure of its base by the measure 1 of its height and dividing the product by 2 ( A bh ). 2 1 A bh 2 b = 3.7 cm, h = 2.4 cm A = ½ (3.7)(2.4) A = 4.44 cm² The area of a parallelogram is computed by multiplying the measure of its base by the measure of its height ( A bh ). A = bh 12 b = 12, h = 7 7 A = (12)(7) A = 84 The area of a trapezoid is computed by taking the average of the measures of the two 1 bases and multiplying this average by the height [ A h(b1 b2 ) ]. 2 3 3 8 A 1 h(b1 b2 ) 2 h = 3, b1 = 3, b2 = 8 A = ½(3)(3 + 8) A = ½(3)(11) A = 16.5 The area of a circle is computed by multiplying Pi times the radius squared ( A r 2 ). Example: What is the area of circle with a radius of 23? A = πr² r = 23 A = (π)(23)² A = (π)(529) A = 1661.9 Julie A. Byrd, Suffolk Public Schools Updated 10/13 8 The circumference of a circle is found by multiplying Pi by the diameter or multiplying Pi by 2 times the radius ( C d or C 2 r ). Example: 14 C = πd C = 2πr d = 14 r = 14/2 = 7 C = (π)(14) C = 2(π)(7) C = 43.98 C = 43.98 The area of any composite figure is based upon knowing how to find the area of the composite parts such as triangles, rectangles and circles. Area of Triangle Area of Rectangle A = ½ bh A = lw b = 4 cm, h = 4 cm l = 4 cm, w = 2 cm A = ½ (4)(4) A = (4)(2) A = 8 cm² A = 8 cm² Area of Figure = Area of Triangle + Area of Rectangle Area of Figure = 8 cm² + 8 cm² Area = 16 cm² Area of Rectangle A = lw l = 20 cm, w = 14 cm A = (14)(20) A = 280 cm2 Area of Semi-circle A= d = 14 cm, r = 7 cm A= A= A= A = 76.93 cm2 Area of Figure = Area of Rectangle + Area of Semi-circle Area of Figure = 280 cm2 + 76.93 cm2 Area = 356.93 cm2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 9 15 in 12 in 9 in Area of Rectangle A = lw l = 15 in, w = 12 in A = (15)(12) A = 180 in2 Area of Semi-circle A= d = 15 in – 9 in = 6 in, r = 3 in A= A= A= A = 14.13 in2 Area of Figure = Area of Rectangle - Area of Semi-circle Area of Figure = 180 in2 – 14.13 in2 Area = 165.87 in2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 10 SOL Practice Items provided by the VDOE, http://www.doe.virginia.gov/testing/sol/sta ndards_docs/mathematics/index.shtml Answers are located on the last page of the booklet. 3. Pablo has a large circular rug on his square-shaped bedroom floor. If the diameter of the rug is equal to the length of the bedroom floor, which is closest to the area of the rug? Area and Perimeter of Composite Plane Figures, SOL 8.11 1. Travis is making a wall hanging out of different colors of glass. The shape of the wall hanging is shown on the grid below. Which is closest to the total amount of glass needed to make the wall hanging? 4. What is the minimum number of the same-sized triangles as the one above that would be required to form the polygon below? 2. Bob wants to paint a rectangular wall that measures 16 ft by 9ft. The wall contains a window with the dimensions shown. Julie A. Byrd, Suffolk Public Schools Updated 10/13 5. What is the area of the parallelogram shown? 11 6. Katie is going to carpet her living room floor and drew the diagram shown. What is the minimum number of square feet of carpet she will need? 7. What is the total area of the figure shown? 8. Leslie built a walkway around a rectangular garden as shown. The walkway is the same length on all sides of the garden. What is the perimeter of the garden? 9. A composite figure is shown. What is the total area of this figure? 10. A rectangle as shown has a length of 0.9 centimeters and a width of 0.4 centimeters. A circle is drawn inside that touches the rectangle at two points. Which is closest to the total area of the shaded region of the rectangle? Julie A. Byrd, Suffolk Public Schools Updated 10/13 12 Testing Information Midpoint Test, 2nd Nine Weeks The Midpoint Test will include questions from standards 8.10 and 8.11 (included in this booklet), as well as questions from standards 8.1a, 8.4 and 8.15, which were taught and tested earlier in the school year. Use the 1st and 2nd Nine Weeks Review Notes for Parents and Students to prepare for this test. The 2nd Nine Weeks Midpoint Test will be administered December 5th through December 10th, 2013. Check with your child’s teacher for the specific testing date. Julie A. Byrd, Suffolk Public Schools Updated 10/13 13 SOL 8.9 The student will construct a three-dimensional model, given the top, side, and/or bottom views. Three-dimensional models of geometric solids can be used to understand perspective and provide tactile experiences in determining two-dimensional perspectives. Three-dimensional models of geometric solids can be represented on isometric paper. Example 1: Given the views above, students should be able to construct a threedimensional model. Example 2: A figure has the views shown. Students should be able to identify the three dimensional model. Julie A. Byrd, Suffolk Public Schools Updated 10/13 14 SOL Practice Items provided by the VDOE, http://www.doe.virginia.gov/testing/sol/sta ndards_docs/mathematics/index.shtml Answers are located on the last page of the booklet. 3. A figure has the bottom and the left-side views shown, and its front view is shaded. Which represents the figure? Three-Dimensional Figures, SOL 8.9 1. Three different views of a three-dimensional figure constructed from cubes are shown. Which of the following figures could these views represent? 4. Three different views of a three dimensional figure are shown. 2. A three dimensional figure is constructed from identical cubes. Three views of the figure are shown. 5. His shows three different views of a three dimensional figure constructed from cubes. Which could be this figure? Which of the following could be the three dimensional figure? Julie A. Byrd, Suffolk Public Schools Updated 10/13 15 6. Which three dimensional figure in the position shown most likely has the top view shown? (top view) 7. This shows three different views of a three-dimensional figure made from cubes. 9. The front view of a threedimensional figure using identical cubes is shown. Identify each three-dimensional figure that has this front view. 10. Which could represent the front view of this figure? Which could be a drawing of the figure? 8. A figure has the views shown. Which represents the figure? Julie A. Byrd, Suffolk Public Schools Updated 10/13 11. Which three-dimensional figure could be represented by these three views? 16 Julie A. Byrd, Suffolk Public Schools Updated 10/13 17 SOL 8.7 The student will a) investigate and solve practical problems involving volume and surface area of prisms, cylinders, cones, and pyramids; b) describe how changing one measured attribute of a figure affects the volume and surface area. A rectangular prism can be represented on a flat surface as a net that contains six rectangles, two that have measures of the length and width of the base, two that have measures of the length and height, and two that have measures of the width and height. The surface area of a rectangular prism is the sum of the areas of all six faces (SA = 2lw + 2lh + 2wh). Example: Carl is covering a rectangular prism-shaped box with cloth. l = 8 in. w = 12 in. h = 2 in. What is the minimum amount of cloth Carl needs to cover the entire box? SA = 2lw + 2lh + 2wh SA = 2(8)(12) + 2(8)(2) + 2(12)(2) SA = 2(96) + 2(16) + 2(24) SA = 192 + 32 + 48 SA = 272 inches2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 18 A triangular prism can be represented on a flat surface as a net that contains three rectangles and two triangles that form the bases of the prism. The surface area of a triangular prism is the sum of the areas of all five faces (SA = hp + 2B), where h is the height of the prism and p is the perimeter of the base. Example: Derek bought a Toblerone chocolate bar for his mother for Mother’s Day. How much wrapping paper would he need to cover the box? 25 cm 5 cm 5 cm 6 cm 4 cm SA = hp + 2B h = height of prism = 25 cm p = perimeter of base = 5 + 5 + 6 = 16 cm B = area of base (triangle) = b = base of triangle, h = height of triangle B= B = (3)(4) B = 12 cm2 SA = hp + 2B SA = (25)(16) + (2)(12) SA = 400 + 24 SA = 424 cm2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 19 A cylinder can be represented on a flat surface as a net that contains two circles (bases for the cylinder) and one rectangular region whose length is the circumference of the circular base and whose width is the height of the cylinder. The surface area of the cylinder is the area of the two circles and the rectangle (SA = 2r 2 + 2rh). Example: A cylinder-shaped barrel has a diameter of 3 feet and a height of 4.5 feet. If the barrel is empty, which is closest to the minimum amount of paper needed to completely cover the barrel? *Remember, the radius is half of the diameter. Be careful to use the correct value. If the diameter is 3 feet, then the radius is 1.5 feet. SA = 2r 2 + 2rh SA = 2(1.5 2) + 2(1.5)h SA = 2(2.25) + 2(1.5)h SA = 2(3.14)(2.25) + 2(3.14)(1.5)(4.5) SA = 2(7.065) + 2(21.195) SA = 14.13 + 42.39 SA = 56.52 feet2 A circular cone is a geometric solid whose base is a circle and whose side is a surface composed of line segments connecting points on the base to a fixed point, the vertex, not on the base. o The lateral area of a circular cone is the area of the surface connecting the base with the vertex and is equal to rl, where l is the slant height. o The area of the base of a circular cone is r 2. The total surface area of a circular cone is r 2 + rl. Example: Find the surface area of a cone that has a radius of 4 centimeters and a slant height of 9 centimeters. SA = r 2 + rl SA = (42) + (4)9 SA = (16) + (4)9 SA = (3.14)(16) + (3.14)(4)(9) SA = (50.24) + (113.04) SA = 163.28 cm2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 20 A pyramid is a polyhedron with a base that is a polygon and other faces that are triangles with a common vertex. o The lateral area of a pyramid is the sum of the areas of the triangular faces. o The area of the base of a pyramid is the area of the polygon which is the base. o The total surface area of a pyramid is the sum of the lateral area and the area of the base. 1 lp + B where l is the length of the face (slant 2 height), p is the perimeter of the base, and B is the area of the base. The total surface area of a pyramid is Example: What is the surface area of a pyramid with dimensions shown? 7 ft The perimeter is found by adding the length of each side of the base: 3 + 3 +3 + 3 = 12 ft 5 ft 3 ft 3 ft The area of the base is found by multiplying the length times the width of the base: (3)(3) = 9 ft 1 SA = lp + B 2 SA = 1 (7)(12) + 9 2 SA = 1 (84) + 9 2 SA = 42 + 9 SA = 51 feet2 Julie A. Byrd, Suffolk Public Schools Updated 10/13 OR 84 ÷ 2 + 9 21 The volume of a rectangular prism is computed by multiplying the area of the base, B, (length times width) by the height of the prism (V = lwh). Example: Joseph is filling a box with peanuts. 25 cm l = 10 cm w = 25 cm h = 20 cm 20 cm 10 cm If the box is empty, what is closest to the amount of peanuts the box will hold? V = lwh V = (10)(25)(20) V = (10)(500) V = 5,000 cm3 The volume of a triangular prism is also computed by multiplying the area of the base, B, (one-half the base of the triangle times the height/altitude of the triangle) by the height of the prism (V = Bh). Example: The Toblerone company has just constructed a new box for their chocolate. How much chocolate will each of the new boxes hold? V= Bh 25 cm 5 cm 6 cm 5 cm h = height of prism = 25 cm B = area of base (triangle) = b = base of triangle, h = height of triangle 4 cm B= B = (3)(4) B = 12 cm2 V= Bh V = (12) (25) V = 300 cm3 Julie A. Byrd, Suffolk Public Schools Updated 10/13 22 The volume of a cylinder is computed by multiplying the area of the base, B, (r 2) by the height of the cylinder (V = r 2h). Example: A cylinder-shaped barrel has a diameter of 3 feet and a height of 4.5 feet. If the barrel is empty, what is closest to the minimum amount of water needed to completely fill the barrel? *Remember, the radius is half of the diameter. Be careful to use the correct value. If the diameter is 3 feet then the radius is 1.5 feet. V = r 2h V = (1.5 2)h V = (2.25)h V = (3.14)(2.25)(4.5) V = 31.8 feet3 The volume of a cone is 1 r 2h, where h is the height and r 2 is the area of the 3 base. Example: Find the volume of a cone that has a radius of 4 centimeters and a height of 9 centimeters. 1 V = 3 r 2h 1 V = 3 (42)(9) 1 V = 3 (3.14)(16)(9) 1 V = 3 (452.16) V = 150.72 cm3 Julie A. Byrd, Suffolk Public Schools Updated 10/13 OR 452.16 ÷ 3 23 The volume of a pyramid is 1 Bh, where B is the area of the base and h is the height 3 (altitude). 7 ft 5 ft 3 ft 3 ft The area of the base is found by multiplying the length times the width of the base: (3)(3) = 9 ft 1 V = 3 Bh 1 V = 3 (9)(5) 1 V = 3 (45) OR 45 ÷ 3 V = 15 feet c) describe how changing one measured attribute of a figure affects the volume and surface area. *When one attribute of a prism is changed through multiplication or division, the volume increases or decreases by the same factor. Example: Two triangular prisms shown have bases with the same area. Julie A. Byrd, Suffolk Public Schools Updated 10/13 24 SOL Practice Items provided by the VDOE, http://www.doe.virginia.gov/testing/sol/sta ndards_docs/mathematics/index.shtml 4. What is the surface area of the rectangular prism shown? Answers are located on the last page of the booklet. Volume and Surface Area, SOL 8.7 1. What is the surface are of a rectangular prism with the dimensions shown? 2. The radius of the base of a cone is 4 inches. The slant height of the cone is 6 inches. Which is closest to the surface area of the cone? 3. What is the volume of a squarebased pyramid with base side lengths of 16 meters, a slant height of 17 meters, and height of 15 meters? Julie A. Byrd, Suffolk Public Schools Updated 10/13 5. Which is closest to the volume of a cylinder with the dimensions shown? 6. What is the surface area of a cube with the measurements shown? 7. If all measurements of the right prisms and cylinders are in inches, which container has the greatest volume? 25 8. Which statement about the volumes of the two prisms shown below, are true? 12. Two triangular prisms shown have bases with the same area. The volume of prism N can be found by multiplying the volume of prism M by what scale factor? 9. Which is the closest to the surface are of a cone with the dimensions shown? 10. The volume of a square-based pyramid is 588 cubic inches. The height of this pyramid is 9 inches. What is the area of the base of this pyramid? 11. A triangular prism is shown. What is the total surface area of the prism? Julie A. Byrd, Suffolk Public Schools Updated 10/13 13. Brian purchased a trophy in the shape of a square pyramid for the most valuable player on his lacrosse team. The trophy had a slant height of 4 inches and each side of its base measured 4 inches. Brian wanted to engrave on the four sides of the trophy, but not on the base of the trophy. How many square inches of the trophy were available for engraving? 26 14. A paper weight mold in the shape of a square pyramid is filled with molten glass. How many cubic inches of molten glass are needed to fill the paper weight? 15. Megan wrapped a present inside a cube-shaped box. The box had an edge length of 4 inches. How many square inches of paper were needed to wrap the box, if there was no overlap? 16. Anna built a prism (Prism A) in the shape of a cube out of wood. The side length of the cube measured 18 inches in length. Anna built another prism (Prism B) with the same dimensions as the cube, except she doubled its height. Julie A. Byrd, Suffolk Public Schools Updated 10/13 Question 16 continued… How does the volume of the two prisms compare? How does the surface area of the two prisms compare? Find the volume and surface area of Prism A and Prism B? 27 Testing Information 2nd Nine Weeks Test The 2nd Nine Weeks Test will include questions from all standards taught since the beginning of the school year. Use the 1st and 2nd Nine Weeks Review Notes for Parents to prepare for the 2nd Nine Weeks Test. The 2nd Nine Weeks Test will be administered the week of January 16, 2014. Check with your child’s teacher for the specific testing date. The following pages contain links to video clips, vocabulary lists, and activities that can be used to review math information that is relevant for this grading period. Julie A. Byrd, Suffolk Public Schools Updated 10/13 28 Math Smarts! Math + Smart Phone = Math Smarts! Need help with your homework? Wish that your teacher could explain the math concept to you one more time? This resource is for you! Use your smart phone and scan the QR code and instantly watch a 3 to 5 minute video clip to get that extra help. (These videos can also be viewed without the use of a smart phone. Click on the links included in this document.) Directions: Using your Android-based phone/tablet or iPhone/iPad, download any QR barcode scanner. How do I do that? 1. Open Google Play (for Android devices) or iTunes (for Apple devices). 2. Search for “QR Scanner.” 3. Download the app. After downloading, use the app to scan the QR code associated with the topic you need help with. You will be directed to a short video related to that specific topic! It’s mobile math help when you need it! So next time you hear, “You’re always on that phone” or “Put that phone away!” you can say “It’s homework!!!” Access this document electronically on the STAR website through Suffolk Public Schools. (http://star.spsk12.net/math/MSInstructionalVideosQRCodes.pdf) PLEASE READ THE FOLLOWING: This resource is provided as a refresher for lessons learned in class. Each link will connect to a YouTube or TeacherTube video related to the specific skill noted under “Concept.” Please be aware that advertisements may exist at the beginning of each video. Julie A. Byrd, Suffolk Public Schools Updated 10/13 29 SOL Link 8.7 Solving problems involving volume and surface area of prisms, cylinders, and pyramids http://www.youtube.com/watch?v=AJYzIbXzVkA 8.7 Solving problems involving volume of cubes, cylinders, pyramids, and cones http://www.youtube.com/watch?v=Uk7d88v8kmA 8.7 Determining surface area using manipulatives http://vimeo.com/album/1612914/video/24480979 8.7 Determining volume using manipulatives http://vimeo.com/album/1612914/video/24481323 8.7 Solving practical problems involving volume and surface area of prisms, cylinders, cones, and pyramids COMING SOON! 8.9 Constructing three-dimensional models COMING SOON! 8.10 Applying the Pythagorean Theorem https://www.youtube.com/watch?v=QNl_yb8doRk Julie A. Byrd, Suffolk Public Schools Updated 10/13 QR Code 30 SOL Link 8.10 Verifying the Pythagorean Theorem https://www.youtube.com/watch?NR=1&v=uaj0XcLtN5c&feature=endscreen Solving area and perimeter problems involving composite plane 8.11 figures https://www.youtube.com/watch?v=tFRCEdydcEk Julie A. Byrd, Suffolk Public Schools Updated 10/13 QR Code 31 Vocabulary SOL 8.10 hypotenuse The side opposite the right angle in a right triangle legs The two sides of a right triangle that form the right angle Pythagorean Theorem In a right triangle, the square of the length of the hypotenuse c is equal to the sum of the squares of the lengths of the legs a and b. c2 = a2 + b2 Pythagorean triple A set of three integers that satisfy the Pythagorean Theorem right angle An angle that measure 90 degrees right triangle A triangle having one right angle SOL 8.11 area The amount of space taken up in a plane by a figure perimeter The distance around a polygon SOL 8.7 pyramid Julie A. Byrd, Suffolk Public Schools Updated 10/13 A polyhedron with a base that is a polygon and other faces that are triangles with a common vertex 32 radius The distance from the center of a circle to any point on the circle surface area The sum of the areas of all the faces of a three-dimensional figure volume The number of cubic units needed to fill the space occupied by a solid cone cylinder A geometric solid whose base is a circle and whose side is a surface composed of line segments connecting points on the base to a fixed point, the vertex, not on the base A solid whose bases are congruent, parallel circles, connected with a curved side diameter The distance across a circle through its center prism A polyhedron with two parallel, congruent faces called bases lateral area of a pyramid The sum of the areas of the triangular faces lateral area of a cone The area of the surface connecting the base with the vertex and is equal to rl vertex The point of intersection of 2 or more line segments attribute A characteristic of a figure Julie A. Byrd, Suffolk Public Schools Updated 10/13 33 Released Test Answers (2nd Nine Weeks) SOL 8.10 (Pythagorean Theorem) SOL 8.9 (continued) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 8. A 9. F H H D H H D J H B G D SOL 8.11 (Area and Perimeter) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. C G C G H C B 76 feet D B SOL 8.9 (Three-Dimensional Models) 1. 2. 3. 4. 5. 6. 7. G D F C B G F Julie A. Byrd, Suffolk Public Schools Updated 10/13 10. D 11. A SOL 8.7 (Volume and Surface Area) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. D H A D J B J C G A 36 cm2 4 32 sq. in 12 in3 96 in2 a) The volume of Prism B is twice the volume of Prism A b) The surface area of Prism B is greater than the surface area of Prism A. The surface area of the four sides of Prism B are twice the surface area of the four sides of Prism A, and the surface are of the two bases of each prism are the same. c) Volume of Prism A = 5,832 in2 S.A. of Prism A = 1,944 in2 Volume of Prism B = 11,644 in3 S.A. of Prism B = 3,240 in3
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