10-6 Solid Figures Learn to name solid figures. Course 1 10-6 Solid InsertFigures Lesson Title Here Vocabulary polyhedron face edge vertex prism base pyramid cylinder cone Course 1 10-6 Solid Figures A polyhedron is a three-dimensional object, or solid figure, with flat surfaces, called faces, that are polygons. When two faces of a solid figure share a side, they form an edge. On a solid figure, a point at which three or more edges meet is a vertex (plural: vertices). Course 1 10-6 Solid Figures Try This: Example 1 Identify the number of faces, edges, and vertices on each solid figure. 6 faces A. 12 edges 8 vertices B. 5 faces 9 edges 6 vertices Course 1 10-6 Solid Figures A prism is a polyhedron with two congruent, parallel bases, and other faces that are all parallelograms. A prism is named for the shape of its bases. Course 1 10-6 Solid Figures A cylinder also has two congruent, parallel bases, but bases of a cylinder are circular. Cylinders are not polyhedra because not every surface is a polygon. Course 1 10-6 Solid Figures A pyramid has one polygon shaped base, and the other faces are triangles that come to a point. A pyramid is named for the shape of its base. Course 1 10-6 Solid Figures A cone has a circular base and a curved surface that comes to a point. Cones are not polyhedra because not every surface is a polygon. Helpful Hint The point of a cone is called its vertex. Course 1 10-6 Solid Figures Additional Example 2A: Naming Solid Figures Name the solid figures represented by the object. There is a curved surface. A. The figure is not a polyhedron. There are two congruent, parallel bases. The bases are circles. The figure represents a cylinder. Course 1 10-6 Solid Figures Additional Example 2B: Naming Solid Figures Name the solid figures represented by the object. B. All the faces are flat and are polygons. The figure is a polyhedron. There is one base and the other faces are triangles that meet at a point, so the figure is a pyramid. The base is a triangle. The figure is a triangular pyramid. Course 1 10-6 Solid Figures Additional Example 2C: Naming Solid Figures Name the solid figures represented by the object. C. All the faces are flat and are polygons. The figure is a polyhedron. There are two congruent, parallel bases, so the figure is a prism. The bases are rectangles. The figure is a rectangular prism. Course 1 10-6 Solid Figures Try This: Example 2A Name the solid figures represented by the object. A. All the faces are flat and are polygons. The figure is a polyhedron. There is one base and the other faces are triangles that meet at a point, so the figure is a pyramid. The base is a square. The figure is a square pyramid. Course 1 10-6 Solid Figures Try This: Example 2B Name the solid figures represented by the object. B. All the faces are flat and are polygons. The figure is a polyhedron. There are two congruent, parallel bases, so the figure is a prism. The bases are rectangles. The figure is a rectangular prism. Course 1 10-6 Solid Figures Try This: Example 2C Name the solid figures represented by the object. There is a curved surface. C. The figure is not a polyhedron. There are two congruent, parallel bases. The bases are circles. The figure represents a cylinder. Course 1 10-7 Surface Area Learn to find the surface areas of prisms, pyramids, and cylinders. Course 1 10-7 Surface Insert Lesson Area Title Here Vocabulary surface area net Course 1 10-7 Surface Area The surface area of a solid figure is the sum of the areas of its surfaces. To help you see all the surfaces of a solid figure, you can use a net. A net is the pattern made when the surface of a solid figure is laid out flat showing each face of the figure. Course 1 10-7 Surface Area Additional Example 1A: Finding the Surface Area of a Prism Find the surface area S of the prism. A. Method 1: Use a net. Draw a net to help you see each face of the prism. Use the formula A = lw to find the area of each face. Course 1 10-7 Surface Area Additional Example 1A Continued A: A = 5 2 = 10 B: A = 12 5 = 60 C: A = 12 2 = 24 D: A = 12 5 = 60 E: A = 12 2 = 24 F: A = 5 2 = 10 Add the areas of each face. S = 10 + 60 + 24 + 60 + 24 + 10 = 188 The surface area is 188 in2. Course 1 10-7 Surface Area Additional Example 1B: Finding the Surface Area of a Prism Find the surface area S of each prism. B. Method 2: Use a three-dimensional drawing. Find the area of the front, top, and side, and multiply each by 2 to include the opposite faces. Course 1 10-7 Surface Area Additional Example 1B Continued Front: 9 7 = 63 63 2 = 126 Top: 9 5 = 45 45 2 = 90 Side: 7 5 = 35 35 2 = 70 S = 126 + 90 + 70 = 286 Add the areas of each face. The surface area is 286 cm2. Course 1 10-7 Surface Area Try This: Example 1A Find the surface area S of the prism. A. Method 1: Use a net. 3 in. 6 in. 11 in. 11 in. 3 in. A 6 in. 3 6 in. 3 in. in. B C D F E 3 in. Draw a net to help you see each face of the prism. Use the formula A = lw to find the area of each face. Course 1 10-7 Surface Area Try This: Example 1A A: A = 6 3 = 18 B: A = 11 6 = 66 C: A = 11 3 = 33 D: A = 11 6 = 66 11 in. E: A = 11 3 = 33 3 in. A 6 in. 3 6 in. 3 in. in. B C D F F: A = 6 3 = 18 Add the areas of each face. S = 18 + 66 + 33 + 66 + 33 + 18 = 234 The surface area is 234 in2. Course 1 E 3 in. 10-7 Surface Area Try This: Example 1B Find the surface area S of each prism. B. Method 2: Use a three-dimensional drawing. top front 8 cm 6 cm side 10 cm Find the area of the front, top, and side, and multiply each by 2 to include the opposite faces. Course 1 10-7 Surface Area Try This: Example 1B Continued top front 8 cm 6 cm Front: 10 8 = 80 Top: Side: 10 6 = 60 8 6 = 48 side 10 cm 80 2 = 160 60 2 = 120 48 2 = 96 S = 160 + 120 + 96 = 376 Add the areas of each face. The surface area is 376 cm2. Course 1 10-7 Surface Area The surface area of a pyramid equals the sum of the area of the base and the areas of the triangular faces. To find the surface area of a pyramid, think of its net. Course 1 10-7 Surface Area Additional Example 2: Finding the Surface Area of a Pyramid Find the surface area S of the pyramid. S = area of square + 4 (area of triangular face) 1 S = s2 + 4 (__bh) 2 1 S = 72 + 4 ( __ 7 8) Substitute. 2 S = 49 + 4 28 S = 49 + 112 S = 161 The surface area is 161 ft2. Course 1 10-7 Surface Area Try This: Example 2 Find the surface area S of the pyramid. 5 ft 5 ft 5 ft Course 1 S = area of square + 4 (area of triangular face) 10 ft 1 S = s2 + 4 (__bh) 2 1 S = 52 + 4 ( __ 5 10) Substitute. 2 10 ft S = 25 + 4 25 S = 25 + 100 S = 125 The surface area is 125 ft2. 10-7 Surface Insert Lesson Area Title Here Lesson Quiz Find the surface area of each figure. Use 3.14 for . 1. rectangular prism with base length 6 ft, width 5 ft, and height 7 ft 214 ft2 2. cylinder with radius 3 ft and height 7 ft 188.4 ft2 3. Find the surface area of the figure shown. 208 ft2 Course 1
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