Definition:
An icosahedron is a regular polyhedron with 20
congruent
equilateral triangular
faces. It is one of the five
Platonic solids.

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An icosahedron is a regular polyhedron that has 20 faces. All the faces are equilateral triangles and are all congruent, that is, all the same size. It is one of the five Platonic solids.

Faces | 20. Each is an equilateral triangle |

Edges | 30 |

Vertices | 12 |

- Definition and properties of a pyramid
- Oblique and right pyramids
- Volume of a pyramid
- Surface area of a pyramid

- Cylinder - definition and properties
- Oblique cylinders
- Volume of a cylinder
- Volume of a partially filledcylinder
- Surface area of a cylinder

- Definition of a cone
- Oblique and Right Cones
- Volume of a cone
- Surface area of a cone
- Derivation of the cone area formula
- Slant height of a cone

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