A bus stop is barricaded from the remaining part of the road by using 50 hollow cones made of recycl...

Question

A bus stop is barricaded from the remaining part of the road by using 50 hollow cones made of recycled cardboard Each one has a base diameter of 40cm and height 1m If the outer side of each of the cones is to be painted and the cost of painting is 25 per m2 what will be the cost of painting all these cones Use 314 and 104 102

Accepted Answer

ANSWER It is given that Radius of the cone 20cm 02m Height of the cone 1m We know that Slant height l r2 h2 By substituting the values l 022 12 On further calculation l 004 1 104 So we get l 102m We know that The curved surface area of cone rl By substituting the values Curved surface area of cone 314 02 102 On further calculation The curved surface area of cone 064056 m2 So the curved surface area of 50 cones 50 064056 32028 m2 It is given that The cost of painting 25 per m2 So the cost of painting 32028 m2 area 25 32028 80070 Therefore the cost of painting all of these cones is 80070

RS Aggarwal Solutions Class 9 Mathematics Solutions for Volume And Surface Area Of Solids Exercise 15C in Chapter 15 - Volume And Surface Area Of Solids