Question

The cost of painting the outer curved surface of a cylinder at rs.1.50 per cm square is rs.660, if the height of the cylinder is 0.1 m find the radius of its base.

Answer 1

Answer:

r = 35cm

Step-by-step explanation:

the curved surface area of the cylinder = 660/1.50 = 440cm^2

2pieRH = 440

2 * 22/7 * r * 2 = 440

88/7 * r = 440

r = 440 * 7/88

r = 5 * 7

r = 35cm

Answer 2

The cost of painting the outer curved surface of a cylinder at Rs 1.50 per cm² is Rs. 660. if the height of the cylinder is 0.1 m.

We have to find the radius of its base.

curved surface area of cylinder = total cost/cost rate of painting

= (660Rs)/(1.5Rs/cm²)

= 440 cm²

let radius of its base is R.

height of cylinder , h = 0.1 m = 10 cm

formula of curved surface area of cylinder = 2πRh

⇒ 440 cm² = 2 × 22/7 × R × 10

⇒440 = 44/7 × R × 10

⇒70 = R × 10

⇒R = 7 cm

Therefore the radius of base of cylinder is 7 cm.