# Chapter 12 Vocabulary – Surface area and Volume of Solids

Word Definition
center of a sphere see sphere
chord of a sphere a segment whose endpoint are on a sphere
cone a solid has one circular base and a vertex that is not on the same plane as the base
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
cross section the intersection of a plane and a solid
cube a polyhedron with six congruent square faces
cylinder a solid with two congruent bases that lie in parallel planes
dodecahedron a polygon with twelve faces
diameter of a sphere a chord that contains the center of a sphere; the distance across a sphere through its center
edge of a polyhedron a line segment formed by the intersection of two faces of a polyhedron
face of a polyhedron see polyhedron
great circle the intersection of a sphere and a plane that contains the center of the sphere
hemisphere half a sphere, formed when a great circle separates a sphere into congruent halves
icosahedron a polyhedron with twenty faces
lateral area the of the areas of the lateral faces of a polyhedron or other solid with one or two bases
lateral edges of a prism the segments connecting the corresponding vertices of the bases of a prism
lateral faces of a prism the faces of a prism that are parallelograms formed by connecting the corresponding vertices of the bases of the prism
oblique prism a prism with lateral edges that are not perpendicular to the bases
net the two-dimensional representation of the faces of a polyhedron
platonic solids five regular polyhedra, named after the Greek mathematician and philosopher Plato
polyhedron a solid that is bounded by polygons, called faces, that enclose a single region of space
prism a polyhedron with two congruent faces, called bases, that lie in parallel planes
pyramid a polyhedron in which the base is a polygon and the lateral faces are triangles with ac common vertex, called the vertex of the pyramid
octahedron a polyhedron with eight faces
regular polyhedron a convex polyhedron in which all of the faces are congruent regular polygons
regular pyramid a pyramid that has a regular polygon for a base and in which the segment joining the vertex and center of the base is perpendicular to the base
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
right cylinder a cylinder in which the segment joining the centers of the bases is perpendicular to the bases
right prism a prism in which each lateral edge is perpendicular to both bases
radius of a sphere a segment from the center of a sphere to a point on the sphere; the distance from the center of the sphere to any point on the sphere
slant height of a regular pyramid the height of a lateral face of the regular pyramid
sphere the set of all points equidistant from a given point called the center of the sphere
similar solids two solids with the same type with equal ratios of corresponding linear measure, such as heights or radii
surface area the sum of the areas of the faces of a polyhedron or other solid
tetrahedron a polyhedron with four faces
vertex of a polyhedron a point where three or more edges of a polygon meet
vertex of a cone see cone
vertex of a pyramid see pyramid
volume of a solid the number of cubic units contained int he interior of a solid
lateral surface of a cone consists of all segments that connect the vertex with points on the edge of the base