# Frustum of a Pyramid

The **frustum of a pyramid** or **truncated pyramid **is the result of cutting a pyramid by a plane parallel to the base and separating the part containing the apex.

The **lateral **faces of a pyramidal frustum are trapezoids.

The **height** of the pyramidal frustum is the perpendicular distance between the **bases**.

The **apothem** is the height of any of its sides.

#### Unfold of a Pyramidal Frustum

#### Apothem of a Pyramidal Frustum

To calculate the **apothem of a pyramidal frustum**, the height, the apothem of the biggest base and the apothem of the minor base must be known. Apply the Pythagorean theorem to determine the length of the hypotenuse of the shaded triangle to obtain the apothem:

## Area and Volume of a Pyramidal Frustum

#### Example

Calculate the lateral area, surface area and volume of the truncated square pyramid whose larger base edge is 24, smaller base edge is 14 cm and whose lateral edge is 13 cm.