1. Chapter 12: Surface Area and Volume of Solids

2. Polyhedron
A solid that is bounded by polygons, called faces, that enclose a single region of space.
Plural is polyhedral or polyhedrons

3. Face
One of the flat surfaces that make a polyhedron.

4. Edge
A line segment formed by the intersection of two faces of a polyhedron.

5. Vertex
A point where three or more edges of a polyhedron meet.

6. Base
One of two congruent faces of a polyhedron

7. Regular Polyhedron
A convex polyhedron in which all of the faces are congruent regular polygons.

8. Convex Polyhedron
A polyhedron is convex if any two points on its surface can be connected by a segment that lies entirely inside or on the polyhedron. If this segment goes outside the polyhedron, then the polyhedron is nonconvex or concave.
convex
concave

9. Platonic Solids
A convex polyhedron where every face is an identical regular polygon

10. Tetrahedron
A polyhedron with four faces

11. Cube
A polyhedron with six congruent square faces

12. Octahedron
A polyhedron with eight faces

13. Dodecahedron
A polyhedron with twelve faces

14. Icosahedron
A polyhedron with twenty faces

15. Cross Section
The intersection of a plane and a solid

16. Prism
A polyhedron with two congruent faces called bases that lie in parallel planes.

17. Lateral Faces
The faces of a prism that are parallelograms formed by connecting the corresponding vertices of the bases of the prism

18. Lateral Edges
The segments connecting the corresponding vertices of the bases of a prism

19. Surface Area
The sum of the areas of the faces of a polyhedron or other solid

20. Lateral Area
The sum of the areas of the lateral faces of a polyhedron or other solid with one or two bases.

21. Net
The two-dimensional representation of the faces of a polyhedron

22. Right Prism
A prism in which each lateral edge is perpendicular to both bases

23. Stop for today.

24. Oblique Prism
A prism with lateral edges that are NOT perpendicular to the bases

25. Cylinder
A solid with congruent circular bases that lie in parallel planes

26. Right Cylinder
A cylinder in which the segment joining the centers of the bases is perpendicular to both bases

27. Pyramid
A polyhedron in which the base is a polygon and the lateral faces are triangles with a common vertex

28. Vertex of a Pyramid
The common vertex of the triangles which make up the lateral faces of a pyramid.

29. Regular Pyramid
A pyramid that has a regular polygon for a base and in which the segment joining the vertex and the center of the base is perpendicular to the base

30. Slant Height
The height of a lateral face of the regular pyramid

31. Cone
A solid that has one circular base and a vertex that is not in the same plane as the base

32. Vertex of a Cone
The vertex that does not lie in the same plane as the base of a cone

33. Right Cone
A cone in which the segment joining the vertex and the center of the base is perpendicular to the base. The slant height is the distance between the vertex and a point on the base edge.

34. Lateral Surface
Consists of all segments that connect the vertex with points on the edge of the base.

35. Volume
The number of cubic units contained in the interior of a solid

36. Sphere
The set of all points in space equidistant from a given point called the center of the sphere

37. Center
The center of a polygon’s circumscribed circle

38. Radius
A segment whose endpoints are the center of the circle and a point on the circle. The distance from the center of a circle to any point on the circle.
Plural is radii

39. Chord
A segment whose endpoints are on a sphere

40. Diameter
A chord that contains the center of a sphere

41. Great Circle
The intersection of a sphere and a plane that contains the center of the sphere

42. Hemisphere
Half of a sphere, formed when a great circle separates into two congruent halves

43. Similar Solids
Two solids of the same type with equal ratios of corresponding linear measures, such as heights or radii