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polyhedron

a solid figure with many sides, such as a pyramid

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face

a surface forming part of the outside of an object

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edge

a sharp side formed by the intersection of two surfaces of an object

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vertex

the point of intersection of lines or the point opposite the base of a figure

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regular polyhedron

any one of five solids whose faces are congruent regular polygons and whose polyhedral angles are all congruent

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convex

curving or bulging outward

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cross section

a section created by a plane cutting a solid perpendicular to its longest axis

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platonic solids

tetrahedron, cube, regular octahedron, regular dodecahedron, regular icosahedron

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tetrahedron

any polyhedron having four plane faces

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octahedron

any polyhedron having eight plane faces

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dodecahedron

any polyhedron having twelve plane faces

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icosahedron

any polyhedron having twenty plane faces

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prism

a polyhedron with two congruent and parallel faces (the bases) and whose lateral faces are parallelograms

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bases

polygons that make up the bottoms of a polyhedron

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lateral faces

the faces that are not the base of a parallelogram

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right prism

each lateral edge is perpendicular to both bases

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oblique prism

a prism that is not a right prism

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surface area of a polyhedron

the sum of the areas of the faces of the polyhedron

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lateral area of a polyhedron

the sum of the areas of the lateral faces of a polyhedron.

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net

a two-dimensional pattern that you can fold to form a three-dimensional figure

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cylinder

a solid bounded by a cylindrical surface and two parallel planes (the bases)

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right cylinder

A cylinder with the axis perpendicular to both bases.

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lateral area of a cylinder

la=2πrh

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surface area of a cylinder

SA=2πr²+2πrh

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pyramid

a polyhedron having a polygonal base and triangular sides with a common vertex

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regular pyramid

a pyramid whose base is a regular polygon and whose lateral faces are congruent isosceles triangles

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circular cone

base is a circle & it has 1 vertex.

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lateral surface of a cone

LSA = ½PL

(P is the perimeter/circumference of the base, L is the slant height)

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right cone

A cone in which a perpendicular line drawn from the base to the tip (vertex) passes through the center of the base

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sphere

a three-dimensional closed surface such that every point on the surface is equidistant from the center

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center of a sphere

The point inside a sphere that is the same distance from every point on the sphere.

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radius of a sphere

a segment that has one endpoint at the center and the other endpoint on the sphere

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chord of a sphere

a segment whose endpoints are on the sphere

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diameter of a sphere

a segment passing through the center, with endpoints on the sphere

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great circle

a circular line on the surface of a sphere formed by intersecting it with a plane passing through the center

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hemisphere

half of a sphere

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similar solids

solids with the same shape and all their corresponding dimensions are proportional

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