7th Grade Math 3D Geometry 20170213 www.njctl.org Table of Contents 3Dimensional Solids Cross Sections of 3Dimensional Figures Volume • Prisms and Cylinders • Pyramids, Cones & Spheres Surface Area • • • • Prisms Pyramids Cylinders Spheres More Practice/ Review Glossary & Standards Teacher Notes Click on a topic to go to that section Vocabu in the p box the linked to of the p word de 3Dimensional Solids Return to Table of Contents Click below for a website with interactive 3D shapes and nets Polyhedron A polyhedron is a 3D figure whose faces are all polygons. Sort the figures to the appropriate side. Polyhedron Not Polyhedron 3Dimensional Solids Categories & Characteristics of 3D Solids: Prisms 1. Have 2 congruent, polygon bases which are parallel to one another click to reveal 2. Sides are rectangular (parallelograms) 3. Named by the shape of their base Pyramids 1. Have 1 polygon base with a vertex opposite it 2. Sides are triangular click to reveal 3. Named by the shape of their base 3Dimensional Solids Categories & Characteristics of 3D Solids: Cylinders 1. Have 2 congruent, circular bases which are parallel to one another click to reveal 2. Sides are curved Cones 1. Have 1 circular base with a vertex opposite it 2. Sides are curvedclick to reveal 3Dimensional Solids Vocabulary Words for 3D Solids: Polyhedron A 3D figure whose faces are all polygons (Prisms & Pyramids) Face Flat surface of a Polyhedron Edge Line segment formed where 2 faces meet Vertex Point where 3 or more faces/edges meet (pl. Vertices) Name the figure. A Rectangular Prism B Triangular Pyramid C Hexagonal Prism D Rectangular Pyramid E Cylinder F Cone Answer 1 Name the figure. A B C D E F Rectangular Pyramid Triangular Prism Octagonal Prism Circular Pyramid Cylinder Cone Answer 2 Name the figure. A B C D E F Rectangular Pyramid Triangular Pyramid Triangular Prism Hexagonal Pyramid Cylinder Cone Answer 3 Name the figure. A B C D E F Rectangular Prism Triangular Prism Square Prism Rectangular Pyramid Cylinder Cone Answer 4 Name the figure. A B C D E F Rectangular Prism Triangular Pyramid Circular Prism Circular Pyramid Cylinder Cone Answer 5 Faces, Vertices and Edges Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Click Math Practice For each figure, find the number of faces, vertices and edges. Can you figure out a relationship between the number of faces, vertices and edges of 3Dimensional Figures? Euler's Formula Euler's Formula: E + 2 = F + V click to reveal The sum of the edges and 2 is equal to the sum of the faces and vertices. How many faces does a pentagonal prism have? Answer 6 How many edges does a rectangular pyramid have? Answer 7 How many vertices does a triangular prism have? Answer 8 Cross Sections of ThreeDimensional Figures Return to Table of Contents Cross Sections 3Dimensional figures can be cut by planes. When you cut a 3D figure by a plane, the result is a 2D figure, called a cross section. These cross sections of 3D figures are 2 dimensional figures you are familiar with. Look at the example on the next page to help your understanding. Cross Sections A horizontal crosssection of a cone is a circle. Can you describe a vertical crosssection of a cone? Cross Sections A vertical crosssection of a cone is a triangle. Cross Sections A water tower is built in the shape of a cylinder. How does the horizontal crosssection compare to the vertical crosssection? Cross Sections The horizontal crosssection is a circle. The vertical crosssection is a rectangle Which figure has the same horizontal and vertical crosssections? A C B D Answer 9 10 Which figure does not have a triangle as one of its crosssections? C B D Answer A A Triangle B Circle C Rectangle D Trapezoid Answer 11 Which is the vertical crosssection of the figure shown? A Triangle B Circle C Rectangle D Trapezoid Answer 12 Which is the horizontal crosssection of the figure shown? A Triangle B Circle C Square D Trapezoid Answer 13 Which is the vertical crosssection of the figure shown? 14 Misha has a cube and a rightsquare pyramid that are made of clay. She placed both clay figures on a flat surface. Select each choice that identifies the twodimensional plane sections that could result from a vertical or horizontal slice through each clay figure. B Cube cross section is a Square C Cube cross section is a Rectangle (not a square) D RightSquare Pyramid cross section is a Triangle E RightSquare Pyramid cross section is a Square F RightSquare Pyramid cross section is a Rectangle (not a square) From PARCC EOY sample test calculator #11 Answer A Cube cross section is a Triangle Note: cross s you w Volume Return to Table of Contents Volume Volume The amount of space occupied by a 3D Figure The number of cubic units needed to FILL a 3D Figure (layering) click to reveal click to reveal Units3 or cubic units Math Practice Label MP6: At Continu units us answer Ask: Wh use? Volume Activity Lab #1: Volume Activity Math Practice Click the link below for the activity Volume of Prisms & Cylinders Return to Table of Contents Volume Volume of Prisms & Cylinders: Click Area of Base x Height Area Formulas: Rectangle = lw or bh Click Click Triangle = or Circle = r2 Click Volume 8 m 2 m 5 m Answer Find the Volume. Volume Answer Find the Volume. Use 3.14 as your value of . 9 yd 10 yd Answer 15 Find the volume. Answer 16 Find the volume of a rectangular prism with length 2 cm, width 3.3 cm and height 5.1 cm. A B C D Answer 17 Which is a possible length, width and height for a rectangular prism whose volume = 18 cm 3? 18 Find the volume. 50 ft 42 ft 21 ft Answer 47 ft 19 Find the volume. Use 3.14 as your value of . 10 m Answer 6 m Teachers: Use this Mathematical Practice Pull Tab for the next 3 SMART Response slides. Math Practice The nex MP4 & Ask: W see bet prism/c (MP4) Could y your th Why do (MP4) 20 A boxshaped refrigerator measures 12 by 10 by 7 on the outside. All six sides of the refrigerator are 1 unit thick. What is the inside volume of the refrigerator in cubic units? Answer HINT: You may want to draw a picture! Answer 21 What is the volume of the largest cylinder that can be placed into a cube that measures 10 feet on an edge? Use 3.14 as your value of . Answer 22 A circular garden has a diameter of 20 feet and is surrounded by a concrete border that has a width of three feet and a depth of 6 inches. What is the volume of concrete in the path? Use 3.14 as your value of . Teachers: Use this Mathematical Practice Pull Tab for the next SMART Response slide. Math Practice The ne Ask: W will he W A Glass A having a 7.5 cm diameter and standing 12 cm high B Glass B having a 4 cm radius and a height of 11.5 cm Answer 23 Which circular glass holds more water? Use 3.14 as your value of . Before revealing your answer, make sure that you can prove that your answer is correct. Volume of Pyramids, Cones & Spheres Return to Table of Contents Volume Math Practice Given the same diameter and height for each figure, drag them to arrange in order of smallest to largest volume. How many filled cones do you think it would take to fill the cylinder? How many filled spheres do you think it would take to fill the cylinder? Comparing Volume of 3D Shapes Click here for a demonstration comparing volume of cones & spheres with volume of cylinders Volume of a Cone The Volume of a Cone is the volume of a cylinder with the same base area (B) and height (h). What is the formula? Volume of a Sphere The Volume of a Sphere is the volume of a cylinder with the same base area (B) and height (h). What is the formula? Volume How much ice cream can a Friendly’s Waffle cone hold if it has a diameter of 6 in and its height is 10 in? Answer (Just Ice Cream within Cone. Not on Top) 9 in 4 in Answer 24 Find the volume. 25 Find the volume. 5 cm Answer 8 cm Volume If the radius of a sphere is 5.5 cm, what is its volume? Answer 26 What is the volume of a sphere with a radius of 8 ft? Answer 27 What is the volume of a sphere with a diameter of 4.25 in? Volume of a Pyramid The Volume of a Pyramid is the volume of a prism with the same base area (B) and height (h). What is the formula? Note: Pyramids are named by the shape of their base. Volume Example: Find the volume of the pyramid shown below. =5 m m 4 = le e sid n h t g Answer 28 Find the Volume of a triangular pyramid with base edges of 8 in, base height of 6.9 in and a pyramid height of 10 in. 10 in 6.9 in 8 in 29 Find the volume. 7 cm 8 cm Answer 15.3 cm Surface Area Return to Table of Contents Surface Area of Prisms Return to Table of Contents Surface Area Surface Area is the sum of the areas of all outside surfaces of a 3D figure. To find surface area, you must find the area of each surface of the figure then add them together. What type of figure is pictured? 6 in How many surfaces are there? How do you find the area of each surface? 3 in 8 in Surface Area 6 in 3 in 8 in 8 in 3 in 6 in 6 in 6 in 8 in 3 in 3 in 8 in Bottom: 8 x 3 = 24 Left: 6 x 3 = 18 Front: 8 x 6 = 48 Top: 8 X 3 = 24 Right: 6 X 3 = 18 Back: 8 x 6 = 48 Sum: 24 + 24 + 18 + 18 + 48 + 48 = 180 in2 Surface Area: 180 in2 Net Another way that you can visualize the entire surface and calculate the surface area is to create the net of your solid by unfolding it. Below is a the net of a rectangular prism. Back Left Bottom Front Right Top Surface Area using Nets You can also calculate the surface area of our last example by drawing the net, calculating the areas, and adding them together. 48 in2 6 in 18 in2 24 in2 18 in2 24 in2 3 in 8 in 48 in2 Total Surface Area: 18 + 24 + 18 + 24 + 48 + 48 = 180 in2 Arrangement of Unit Cubes Surface Area Activity Click the link below for the activity Lab #2: Surface Area Activity The ne Use this Mathematical Practice Pull Tab for the next 4 SMART Response slides. Math Practice Teachers: Ask: Ho the pro Wha answ A B C Answer 30 Which arrangement of 27 cubes has the least surface area? 31 Which arrangement of 12 cubes has the least surface area? Answer A B C D A B Answer 32 Which arrangement of 25 cubes has the greatest surface area? A B C D E F Answer 33 Which arrangement of 48 cubes has the least surface area? Surface Area Find the surface area of a rectangular shoe box that has a length of 12 inches, a width of 6 inches and a height of 5 inches. 5 in 6 in 12 in Top/Bottom Front/Back Left/Right Surface Area 12 x 6 72 x 2 144 12 x 5 60 x 2 120 6 x 5 30 x 2 60 144 + 120 324 in2 click to reveal click to reveal click to reveal click to reveal Surface Area Name the figure. Find the figure's surface area. Answer Re 7 m Base 3(5)(2) 30 Sum = 14 3 m 5 m Click to reveal the prism's net, if needed 34 How many faces does the figure have? Answer 6 m 2 m 4 m Answer 35 How many area problems must you complete when finding the surface area? 6 m 2 m 4 m 3 36 What is the area of the top or bottom face? Answer 6 m 2 m 4 m 37 What is the area of the left or right face? Answer 6 m 2 m 4 m 38 What is the area of the front or back face? Answer 6 m 2 m 4 m 39 What is the surface area of the figure? Answer 6 m 2 m 4 m Click to reveal the prism's net, if needed 2 1. Draw and label ALL faces; use the net, if it's helpful 2. Find the correct dimensions for each face 3. Calculate the AREA of EACH face 4. Find the SUM of ALL faces 5. Label Answer 5 yd 5 yd 4 yd 9 yd 6 yd Teacher Notes Find the Surface Area Surface Area 5 yd 5 yd 5 yd 4 yd 5 yd 9 yd 6 yd Bottom Rectangle 9 Click x 6 54 4 yd 5 yd 5 yd 4 yd 9 yd 9 yd 6 yd 6 yd Triangles Left/Right Rectangles Click 4 5 Click x 6 x 9 24 / 2 = 12 45 x 2 x 2 24 90 Total Surface Area: 54 + 24 + 90 = 168 yd 2 Click Find the Surface Area Using the Net 5 yd 5 yd 4 yd 9 yd 6 yd Triangles Click 4 x 6 24 / 2 = 12 x 2 24 Middle Rectangle Left/Right Rectangles 9 Click (Same size since isosceles) x 6 5 x 9 = 45 x 2 = 90 Click 54 Total Surface Area: 24 + 54 + 90 = 168 ydClick2 Find the Surface Area 1. Draw and label ALL faces; use the net if it's helpful 2. Find the correct dimensions for each face 3. Calculate the AREA of EACH face 4. Find the SUM of ALL faces 5. Label Answer 9 cm 9 cm 7.8 cm 9 cm 11 cm Surface Area 9 cm 9 cm 7.8 cm 9 cm 11 cm 7.8 cm 11 cm 9 cm Triangles Rectangles Click Click Hint & Answer 9 cm 9 cm 40 Find the surface area of the shape below. 1. Draw use t 2. Find t 50 ft 21 ft 42 ft Hint & Answer 47 ft 3. Ca 4. Find 5 Find the Surface Area 3 cm 9 cm 4 cm 15 cm 5 cm 6 cm Find the Surface Area 3 cm 9 cm 4 cm 15 cm Answer 5 cm 6 cm Trapezoids Click 12 + 6 18 x 4 72 / 2 = 36 x 2 72 Bottom Rectangle Click 6 x 15 90 Top Rectangle Click 12 x 15 180 Side Rectangles Click 5 x 15 75 x 2 150 72 + 90 41 Find the surface area of the shape below. 8 cm 9 cm 10 cm Answer 6 cm 42 Find the surface area of the shape below. 2 cm cm 10 10 cm m 6 c Answer 6 cm Surface Area of Pyramids Return to Table of Contents Surface Area of Pyramids What is a pyramid? Click Polyhedron with one base and triangular faces that meet at a vertex How do you find Surface Area? Click Sum of the areas of all the surfaces of a 3D f igure Find the Surface Area 17.4 cm 8 cm 7 cm Teacher Notes 17.5 cm Bottom Rectangle Front/Back Triangles Left/Right Triangles Answer Find the Surface Area. 56 + 13 Surface Area Find the surface area of a square pyramid with base edge of 4 inches and triangle height of 3 inches. 3 in Base: 4 x 4 = 16 Click Click 4 Triangles: 4 in Surface Area: 16 + 24 = 40 in2 Click Surface Area Find the surface area. Be sure to look at the base to see if it is an equilateral or isosceles triangle (making all or two of the side triangles equivalent!). Click Remaining Triangles (all equal) Hint Click Base 6 in 4 in 3.5 in 4 in 4 in Click Surface Area 43 Which has a greater Surface Area, a square pyramid with a base edge of 8 in and a height of 4 in or a cube with an edge of 5 in? Square Pyramid Cube Answer A B 10 in 8 in 6.9 in 8 in 8 in Answer 44 Find the Surface Area of a triangular pyramid with base edges of 8 in, base height of 4 in and a slant height of 10 in. 11 m 12 m 6.7 m 9 m 9 m Answer 45 Find the Surface Area. Surface Area of Cylinders Return to Table of Contents Surface Area How would you find the surface area of a cylinder? Hint Surface Area Steps 1. Find the area of the 2 circular bases. 2. Find the area of the curved surface (actually, a rectangle). 3. Add the two areas. 4. Label answer. Surface Area Radius Radius Radius H E I G H T Original cylinder Curved Side = Circumference of Circular Base Middle step to get to the net H E I G H T Curved Side = Circumference of Circular Base Net of a cylinder Surface Area Radius Radius H E I G H T H E I G H T Curved Side = Circumference of Circular Base Surface Area Find the surface area of a cylinder whose height is 14 inches and whose base has a diameter of 16 inches. Use 3.14 as your value of . Area of Circles: Click 16 in 14 in Area of Curved Surface = Circumference Height Click Surface Area:Click Answer 46 Find the surface area of a cylinder whose height is 8 inches and whose base has a diameter of 6 inches. Use 3.14 as your value of . Answer 47 Find the surface area of a cylinder whose height is 14 inches and whose base has a diameter of 20 inches. Use 3.14 as your value of . Answer 48 How much material is needed to make a cylindrical orange juice can that is 15 cm high and has a diameter of 10 cm? Use 3.14 as your value of . Answer 49 Find the surface area of a cylinder with a height of 14 inches and a base radius of 8 inches. Use 3.14 as your value of . 50 A cylindrical feed tank on a farm needs to be painted. The tank has a diameter 7.5 feet and a height of 11 ft. One gallon of paint covers 325 square feet. Do you have enough paint? Explain. Note: Use 3.14 as your value of . No Answer Yes Surface Area of Spheres Return to Table of Contents Surface Area A sphere is the set of all points that are the same distance from the center point. Like a circle, a sphere has a radius and a diameter. You will see that like a circle, the formula for surface area of a sphere also includes . Surface Area of a Sphere Radius click to reveal Surface Area If the diameter of the Earth is 12,742 km, what is its surface area? Use 3.14 as your value of . Round your answer to the nearest whole number. 12,742 km Surface Area Try This: Find the surface area of a tennis ball whose diameter is 2.7 inches. Use 3.14 as your value of . Click 2.7 in Answer 51 Find the surface area of a softball with a diameter 3.8 inches. Use 3.14 as your value of . Answer 52 How much leather is needed to make a basketball with a radius of 4.7 inches? Use 3.14 as your value of . Answer 53 How much rubber is needed to make 6 racquet balls with a diameter of 5.7 inches? Use 3.14 as your value of . More Practice / Review Return to Table of Contents 54 Find the volume. 8 mm 15 mm Answer 22 mm 55 Find the volume of a rectangular pyramid with a base length of 2.7 meters and a base width of 1.3 meters, and the height of the pyramid is 2.4 meters. Answer HINT: Drawing a diagram will help! Answer 56 Find the volume of a square pyramid with base edge of 4 inches and pyramid height of 3 inches. Answer 57 Find the Volume. 11 m 12 m 6 m 9 m 9 m 21 ft 14 ft Answer 58 Find the Volume. Use 3.14 as your value of . 8 in 6.9 in Answer 59 Find the Volume. Use 3.14 as your value of . 60 Find the volume. Answer 8.06 ft 8 ft 4 ft 7 ft 61 A cone 20 cm in diameter and 14 cm high was used to fill a cubical planter, 25 cm per edge, with soil. How many cones full of soil were needed to fill the planter? Use 3.14 as your value of . Answer 20 cm 14 cm 25 cm 62 Find the surface area of the cylinder. Use 3.14 as your value of . Answer Radius = 6 cm and Height = 7 cm 63 Find the Surface Area. 11 cm 12 cm Answer 11 cm 64 Find the Surface Area. 9 in 8.3 in 8 in 7 in Answer 9 in 65 Find the volume. 9 in 8.3 in 8 in 7 in Answer 9 in Answer 66 A rectangular storage box is 12 in wide, 15 in long and 9 in high. How many square inches of colored paper are needed to cover the surface area of the box? Answer 67 Find the surface area of a square pyramid with a base length of 4 inches and slant height of 5 inches. 68 Find the volume. 40 m 80 m Answer 70 m Answer 69 A teacher made 2 foam dice to use in math games. Each cube measured 10 in on each side. How many square inches of fabric were needed to cover the 2 cubes? Return to Table of Contents Teacher Notes Glossary & Standards Vocabu in the p box the linked t of the p word de Cone A 3D solid that has 1 circular base with a vertex opposite it. The sides are curved. Back to Instruction Cross Section The shape formed when cutting straight through an object. Triangle Square Trapezoid Back to Instruction Cylinder A solid that has 2 congruent, circular bases which are parallel to one another. The side joining the 2 circular bases is a curved rectangle. shapes that form a cylinder top folding down the 2 circles & rolling the rectangle Cylinder bottom Back to Instruction Face Flat surface of a Polyhedron 1 face 1 face 1 face Back to Instruction Edge Line segment formed where 2 faces meet. 1 edge 1 edge 1 edge Back to Instruction Euler's Formula The sum of the edges and 2 is equal to the sum of the faces and vertices. E + 2 = F + V pyramid: vertices = 4 faces = 4 E + 2 = F + V E + 2 = 4 + 4 E + 2 = 8 E = 6 Back to Instruction Net A 2D pattern of a 3D solid that can be folded to form the figure. An unfolded geometric solid. Solid Solid Net Net Solid Net Back to Instruction Polyhedron A 3D figure whose faces are all polygons. A Polyhedron has NO curved surfaces. Plural: Polyhedra Yes, polyhedron Yes, polyhedron No, not a polyhedron Back to Instruction Prism A polyhedron that has 2 congruent, polygon bases which are parallel to one another. Remaining sides are rectangular parallelograms). Named by the shape of the base. Triangular Prism Hexagonal Prism Octagonal Prism Back to Instruction Pyramid A polyhedron that has 1 polygon base with a vertex opposite it. Remaining sides are triangular. Named by the shape of their base Pentagonal Pyramid Rectangular Pyramid Triangular Pyramid Back to Instruction Surface Area The sum of the areas of all outside surfaces of a 3D figure. 5 3 4 6 3 3 6 u25 5 4 6 24 u2 30 u2 6 4 5 3 6 u25 18 u2 1. Find the area of each surface of the figure 2. Add all of the areas together 18 24 30 6 + 6 SA = 84 units2 Back to Instruction Vertex Point where 3 or more faces/edges meet Plural: Vertices 1 vertex 1 vertex 1 vertex Back to Instruction Volume The amount of space occupied by a 3D Figure. The number of cubic units needed to FILL a 3D Figure (layering). Label: V = ? cylinder filled halfway with water V = ? Prism filled with water Units3 or cubic units Back to Instruction Volume of a Cone A cone is 1/3 the volume of a cylinder with the same base area (B = r2) and height (h). V = ( r2h) ÷ 3 or 1 2h V = r 3 h 6 4 r 1 2h V = r 3 V = 1/3 (4)2(6) V = 32 units3 V = 100.48 u3 Back to Instruction Volume of a Cylinder Found by multiplying the Area of the base (B) and the height (h). Since your base is always a circle, your volume formula for a cylinder is V = Bh V = r2h 4 r h V = r2h 10 V = (4)2(10) V = 160 units3 V = 502.4 u3 Back to Instruction Volume of a Prism Found by multiplying the Area of the base (B) and the height (h). V = Bh The shape of your base matches the name of the prism Rectangular Prism Triangular Prism V = Bh V = (1/2b∆h∆)hprism V = Bh V = (lw)h Back to Instruction Volume of a Pyramid A pyramid is 1/3 the volume of a prism with the same base area (B) and height (h). 1 V = (Bh) ÷ 3 or V = (Bh) 3 The shape of your base matches the name of the pyramid Rectangular Pyramid V = 1/3Bh V = 1/3(lw)h Triangular Pyramid V = 1/3Bh V = (1/2b∆h∆)hpyramid hpyramid h∆ b∆ Back to Instruction Volume of a Sphere A sphere is 2/3 the volume of a cylinder with the same base area (B = r2) and height (h = d = 2r). 6 h = d h = 2r V = 2/3 ( r2h) V = 2/3 r2(2r) V = 4/3 r3 V = 4/3 (6)3 V = 288 u3 V = 904.32 u3 Back to Instruction Standards for Mathematical Practices Throughout this unit, the Standards for Mathematical Practice are used. MP1: Making sense of problems & persevere in solving them. MP2: Reason abstractly & quantitatively. MP3: Construct viable arguments and critique the reasoning of others. MP4: Model with mathematics. MP5: Use appropriate tools strategically. MP6: Attend to precision. MP7: Look for & make use of structure. MP8: Look for & express regularity in repeated reasoning. Additional questions are included on the slides using the "Math Practice" Pulltabs (e.g. a blank one is shown to the right on this slide) with a reference to the standards used. If questions already exist on a slide, then the specific MPs that the questions address are listed in the Pulltab.
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