The formula for lateral surface area of cone is:
where, r = radius of the base of the cone, and
l = length of the lateral side of the cone.
What is the formula for the lateral surface area of the given frustum: Where, R1 = radius of the base L = length of lateral side of the bigger cone of which the frustum is a part R2 = radius of the top surface l = length of lateral height of cone - lateral height of frustum(s) (L - s)