Question

slant height of a frustum of a cone is 4 cm and the circumference of its circular ends are 18 cm and 6 cm find cost of painting its curved surface area at rupees 0.50 per CM square​

Answer 1

given slant height = 4cm
circumference =2πr
18 = 2*22/7*r
r =18*7/2*22
• r=2.8cm
r=6*7/2*22=0.9cm
Similarly, you will find the curved surface area of frustum .
At last, cost of painting= curved surface area of frustum * 0.50per cm^2.