Question

Find the number of coins, 1.5 cm in diameter and 2 mm thickness, to be melted to form a right circular cylinder of height 10 cm and diameter 4.5 cm.​

Answer 1

Answer:

450

Step-by-step explanation:

It is given that diameter of coin, d = 1.5 cm

thickness of coin, I = 2mm = 0.2 cm

Radius of right circular cylinder, r = 2.25 cm

Height of right circular cylinder, h = 10 cm

let the number of coins is n

here n coins are melted to form a right circular cylinder.

volume of n coins = volume of the cylinder

=> n × π(d/2)²I = πr²h

=> n × d²I/4 = r²h

=> n × (1.5)² × 0.2/4 = (2.25)² × 10

=> n = (2.25)² × 10 × 4/{(2.25) × 0.2}

=> 2.25 × 10 × 20

=> 450