Question

Find the number of coins 1.5cm in diameter and 0.2cm thick to be melted to form a right circular cylinder of height 15cn and diameter 6cm.

Answer 1

Answer:

1200 coins

Step-by-step explanation:

(i)

Given, Diameter of coin = 1.5 cm.

Then, radius = 0.75 cm.

Height of the coin = 0.2 cm.

Volume of coin = πr²h

                         = π(0.75)² * 0.2

                         = 0.1125π

(ii)

Given,diameter of right circular cylinder = 6 cm.

Then,radius = 3 cm.

Height of a right circular cylinder = 15 cm.

Volume of right circular cylinder = πr²h

                                                      = π(3)² * 15

                                                      = 135π

∴ Let 'n' coins to be melted to form a right circular cylinder.

⇒ 135π = n * 0.1125π

⇒ n = 1200.

Therefore, number of coins = 1200.

Hope it helps!