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geometry of 3D
Geometry of 3D Shapes
| Term | Definition |
|---|---|
| cone | edges = 0 faces = 1 vertices = 1 |
| pyramid | edges = 6 faces = 4 vertices = 4 |
| cylinder | edges = 0 faces = 2 vertices = 0 |
| sphere | edges = 0 faces = 0 vertices = 0 |
| rectangular prism | edges = 8 faces = 5 vertices = 5 |
| cube | edges = 12 faces = 6 vertices = 8 |
| polyhedron | a solid bounded by polygons that enclose a single region of space |
| faces | polygons that make the sides of a polyhedron |
| edge | a line segment formed by the intersection of two faces |
| vertext | a point where three or more edges meet |
| regular polyhedron | all faces are congruent regular polygons |
| convex | any two points can be connected by a segment that lies entirely inside or on the polyhedron |
| platonic solids | the five regular polyhedrons: tetrahedron, cube, octahedron, dodecahedron, icosahedron |
| prism | a polyhedron with two congruent and parallel bases |
| lateral faces | the faces on a prism that aren't bases |
| lateral edges | the segments connecting the vertices of the base (perimeter of the base) |
| surface area (of a polyhedron) | the sum of all the areas of its faces |
| lateral area (of a polyhedron) | sum of all the areas of its lateral faces |
| net | two dimensional representation of a polyhedron |
| right prism | each lateral edge is perpendicular to both bases |
| oblique prism | lateral edges are not perpendicular to the bases |
| formula: surface area of a pyramid | B + 1/2(Ph) |
| formula: surface area of a prism | 2B + Ph |
| formula: surface area of a cone | πr² + πrL |
| formula: surface area of a cylinder | 2πr² + 2πrh |
| cone | a solid figure that has a circular base and one vertex |
| cylinder | A solid figure with two congruent and parallel circular bases |
| sphere | an object with all points on its surface equally distant from its center; a ball or globe |
| faces | the flat surfaces of a 3-D figure |
| edges | the intersection of faces of a 3-D figure |
| vertices | a corner of a polygon |