Find the best and easiest solution of the ncert class 10 chapter surface areas and volumes Give me the easiest and simple solution of exercise 13.4 question number 3. Please give me the best solution of this question .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.
Given,
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
Now,
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
And, Area of upper circular end = πr22
= 16π
∴ The area of material used = 710 × (2/7) cm2