Question

Find the total surface area of a cylindrical tank of height 2.1m and diameter 0.7 m. Also find the cost of painting at the rate of $9.5 per sq metre.​

Answer 1

$51.21

Explanation

Total surface area of cylindrical tank:

height = h = 2.1m

diameter = 0.7m

radius= diameter +2

r = 0.7 +2=0.35 m

Formula

`(2\pi r{}^(2) ) + (\pi dh)`

`(2 * 3.14 * {0.35}^(2) ) + (3.14 * 0.7 * 2.1)`

`2 * 3.14 * 0.35 {}^(2) = 0.77`

`3.14 * 0.7 * 2.1 = 4.62`

`0.77 + 4.62 = 5.39m {}^(2)`

To find the cost of painting the surface area of tank, multiply the cost of painting per square meter by the total surface area of tank.

Cost of painting

`5.39 * 9.50`

= $51.21