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Frustum of a cone

Drawing of a frustrum cone
The area of the lateral surface of a frustum of a cone can be calculated in the following two ways:

If the length of the lateral surface is given:

A=pi*(r_1+r_2)*a

A = area of the lateral surface

r1 = radius of the small circular end plane

r2 = radius of the big circular end plane

a = length of the lateral surface



If the height of the frustum is given:

A=pi*(r_1+r_2)*sqrt{h^2+(r_2-r_1)^2}

A = area of the lateral surface

r1 = radius of the small circular end plane

r2 = radius of the big circular end plane

h = height of the frustum

Calculate the volume and the area of a frustum of a cone

Drawing of a frustrum cone

Height (h): 
Radius of the small circular end plane (r1): 
Radius of the big circular end plane(r2): 
Length of the lateral surface (a): 
Pi: