Name 11-1 Reteach to Build Understanding Space Figures and Cross Sections 1. Match the descriptions with the diagram. 6 faces 12 edges enVision Geometry savvasrealize.com wwwwwwwMM 3 8 vertices 6+8=12+2 A. Faces of a polyhedron are polygons. Euler's Formula is F+V=E+2, where F is the number of faces, V is the number of vertices, and E is the number of edges. B. Rotating a polygon about an axis of rotation forms a solid with circular cross sections for planes perpendicular to the axis. C. A cross section is the intersection of a plane and a space figure. Cross sections of convex polyhedrons are polygons. 2. Rachel is trying to find a plane that intersects the square pyramid to form an isosceles trapezoid. She has an example of a cross section that is an isosceles triangle from a plane that intersects the pyramid at points A, B, and C. Rachel thinks that if she moves the point of intersection from A to D, then the cross section will be the isosceles trapezoid with the dashed line through D as shown. Explain why she is incorrect. A 3. Draw and describe the cross section formed by the intersection of the rectangular prism with the plane that passes through the midpoint of the top left edge, the midpoint of the top front edge, and the midpoint of the left front edge. 1 Draw points where the plane intersects the edges as described. Connect the points of intersection. Describe the cross section. enVision™ Geometry Teaching Resources C B Name 11-1 Reteach to Build Understanding Space Figures and Cross Sections 1. Match the descriptions with the diagram. 6 faces 12 edges enVision Geometry savvasrealize.com wwwwwwwMM 3 8 vertices 6+8=12+2 A. Faces of a polyhedron are polygons. Euler's Formula is F+V=E+2, where F is the number of faces, V is the number of vertices, and E is the number of edges. B. Rotating a polygon about an axis of rotation forms a solid with circular cross sections for planes perpendicular to the axis. C. A cross section is the intersection of a plane and a space figure. Cross sections of convex polyhedrons are polygons. 2. Rachel is trying to find a plane that intersects the square pyramid to form an isosceles trapezoid. She has an example of a cross section that is an isosceles triangle from a plane that intersects the pyramid at points A, B, and C. Rachel thinks that if she moves the point of intersection from A to D, then the cross section will be the isosceles trapezoid with the dashed line through D as shown. Explain why she is incorrect. A 3. Draw and describe the cross section formed by the intersection of the rectangular prism with the plane that passes through the midpoint of the top left edge, the midpoint of the top front edge, and the midpoint of the left front edge. 1 Draw points where the plane intersects the edges as described. Connect the points of intersection. Describe the cross section. enVision™ Geometry Teaching Resources C B