Question

the outer diameter of a gas cylinder is 20 cm. find the cost of paintnting of its outer curved surface at rs 4 per square centimetre if the height of the cylinder is 70 cm

Answer 1

Hello.......... ^_^

Here is your answer....

Given:-
outer diameter of cylinder = 20cm
height of cylinder (h) = 70cm

radius = diameter/2
radius = 20/2 cm
radius = 10 cm

Curved Surface Area(C.S.A) = 2πrh
$= 2 \times \frac{22}{7} \times 10 \times 70 {cm}^{2} \\ \\ (70 \div 7 = 10) \\ \\ = 2 \times 22 \times 10 \times 10 {cm}^{2} \\ \\ = 4400 {cm}^{2}$

if cost for painting 1cm square = Rs.4
so cost for painting 4400cm square = 4400 X 4 = Rs. 17600



Hope it helps....... ^_^

Answer 2

diameter=20cm
radius=20/2=10cm
height=70cm

$curved \: surface \: are \\ = 2\pi rh$
$= 2 \times \frac{22}{7} \times10 \times 70$
$4400 {cm}^{2}$

$cost \: per \: {m}^{2} = rs \: 4$
$cost \: for \: \: 4400 {cm}^{2} \\ = 4400 \times 4$
= Rs 17600