A wooden stool is in the form of a frustrum of a cone with slant edge 40cm,top diameter 30 cm and bottom diameter 50cm

Question

(@) calculate the perpendicular height of the stool
(B) calculate the total surface area of the stool in terms of m squared
(C) calculate the volume of wood used to make the stool in terms of m squared

Answer 1

Draw a side view
h^2 + 10^2 = 40^2

there are handy formulas for the surface area, or you can think of it as the bottom part of a complete cone, so just subtract the area that was cut off

unless you know the thickness of the wood, it's impossible to know its volume.

Answer 2

a) bottom radius = 25
top radius = 15
difference = 10
so h^2 + 100 = 1600
h = 38.73
area add top, bottom and side
top = pi (225)
bottom = pi(625)
side = pi (25+15)(40)