Geometry

# pyramids

A **pyramid** is a polyhedron that is limited by a base and whose lateral faces are triangles with a common vertex called **vertex of the pyramid**.

The **height** of a pyramid is the distance between the vertex and the plane which contains the base.

A pyramid is **regular** when the base is regular and the vertex projects itself in the center of the polygon.

In a regular pyramid all the lateral edges have the same length and all the lateral faces are equal isosceles triangles. The height of these triangles is called **apothem of the pyramid**.

*Development of a right pyramid and its area*

The

**area of a pyramid**is the addition of the areas of all of its faces.**Exercises**:

1.- Calculate the total area of a square pyramid whose base edge is 10 cm and its height is 12 cm.

2.- Calculate total area of a hexagonal pyramid whose base edge is 16 cm and its lateral edge is 28 cm.

Solutions: 1) 360 cm

^{2}; 2) 1953.12 cm^{2}Obra colocada bajo licencia Creative Commons Attribution Non-commercial Share Alike 3.0 License