Question

A cylindrical container is 84 cm high and has base radius of 4.2 cm. Find the cost of painting its curved
surface at the rate of 8 per 100 sq cm.​

Answer 1

Step-by-step explanation:

Given:- A cylinder with height 84cm and base radius of 4.2cm

Rate of painting is 8 per 100cm²

To find:- Cost of painting the C.A

Proof:-

We know that the C.A of a cylinder = 2πrh

So, r = 4.2

h = 84

So,

C.A = 2 × 3.14 × 4.2 × 84

C.A = 2 × 22 × 4.2 × 12 = 2215.584 cm²

Now, rate of painting = Rs.8 per 100cm²

So, for 1 cm² cost = Rs. 8/100 = Rs.(0.08)

So, Cost of Painting = Rate × Area

Cost = 2215.584 × 0.08 = Rs. 177.24672

We know that,

Rs.177.24672 ≈ Rs.177.25

Thus, approximately Rs.(177.25) is needed for painting the cylinder.

Hope it helped and you understood it........All the best