The frustum is a pyramid that is the result of chopping off the top of a regular pyramid. That is the reason why it is called a truncated pyramid.

The distance between the base and the top of the pyramid is the height and is denoted by h. Similarly, it has a slant height that is denoted by “s” and two bases (top and bottom), whose area is defined by

We need to find the lateral surface area and the volume of Frustum of regular pyramid formula.

\[\large V=\frac{h(B_{1}+B_{2}+\sqrt{B_{1}B_{2}})}{3}\]

\[\large S=\frac{s(P_{1}+P_{2})}{2}\]

Here,
S = Lateral Surface Area

Solved Examples

Question: Find the volume of a frustum of a regular pyramid whose area of bases are 9 cm², 10 cm² respectively and height is 9 cm.

Solution:
Given
B₁ = 9 cm²
B₂ = 10 cm²
h = 9 cm

Volume formula,

V =