Question

A closed metallic cyclinder has its base diameter as 56 cm and it is 2.72 mhigh find the cost of metal used to make it if it costs rs 80 per square metre

Answer 1

R= D/2
= 56/2 cm = 28 cm
H= 2.72 × 100cm = 272 cm
Area = 2πrh (r + h)
= 2 × 22/7 × 28× 272 ( 28 + 272)
= 176 × 272 × 300
= 47,872 cm^2
Cost of metal= ₹( 47,872 × 80) = ₹3,82,976

Answer 2

Solution :-

Diameter = 56 cm 

Radius = 56/2 = 28 cm

Height = 2.72 m = 272 cm

Total surface area of cylinder = 2πrh + 2πr²

⇒ (2*22*28*272)/7 + (2*22*28*28)/7

⇒ (176*272) + (176*28)

⇒ 47872 + 4928

⇒ 52800 cm²

1 sq m = 10000 sq cm

Area in sq m = 52800/10000

= 5.28 sq m

Cost of metal = Rs. 80 per sq m

Total cost = 80*5.28

= Rs. 422.40

Answer.