Question

The slant height of a frustum of a cone is 4m and the perimeter of circular ends are 18m and 16m. Find the cost of painting it's curved surface area at Rs.100 sq.m.

Answer 1

Answer:

C.S.A of frustum = π(r1+r2)l

given

Step-by-step explanation:

given, circumference=18m

2πr= 18

2×22/7r = 18

r= 18×7/2×22

r =63/22m

Also, circumference=16m

2πr=16

r=28/11m

C.S.A of frustum=π (R+r)l

By putting values, we get C.S.A = 68m/sq

Now, cost of painting it's C.S.A = 68×100

= Rs6800