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01/07/2021 1:09 pm
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A fez, the cap used by the Turks, is shaped like the frustum of a cone (see Fig.). If its radius on the open side is 10 cm, radius at the upper base is 4 cm and its slant height is 15 cm, find the area of material used for making it.
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01/07/2021 1:10 pm
For the lower circular end, radius (r1) = 10 cm
For the upper circular end, radius (r2) = 4 cm
Slant height (l) of frustum = 15 cm
The area of material to be used for making the fez = CSA of frustum + Area of upper circular end
CSA of frustum = π(r1+r2)×l
= 210π
Area of upper circular end = πr22
= 16π
∴ The area of material used = 710 × (2/7) cm2