Question

A frustum has diameter 21cm at one end diameter 14cm at the other end and its height inside is 30cm , find the surface of the curved area.

Answer 1

Step-by-step explanation:

Given:

1. Larger diameter of frustum=21cm and larger radius, R=21/2cm.
2. Smaller diameter of frustum=14cm and smaller radius, r=14/2=7cm.
3. Height of frustum=30cm.

To find: CSA of frustum.

Formula of CSA of frustum: π(R+r)×l

=> 22/7×(21/2+7)×30

=> 22/7×35/2×30

=> 55×30

=> 1650cm².