Find the number of metallic circular discs with 1.5 cm base diameter and height 0.2 cm to be melted to form a circular cylinder of height 10 cm and diameter 4.5 cm.
Find the number of metallic circular discs with 1.5 cm base diameter and height 0.2 cm to be melted to form a circular cylinder of height 10 cm and diameter 4.5 cm.

Solution:

Given height of the circular cylinder, h = 10 cm

Diameter of circular cylinder = 4.5 cm

So radius, r = 4.5/2 = 2.25 cm

Volume of circular cylinder = r2h

= ×2.252×10 = 50.625 cm3

Base diameter of circular disc = 1.5 cm

So radius, r = 1.5/2 = 0.75 cm

Height of the circular disc, h = 0.2 cm

Volume of circular disc = r2h

= ×0.75×0.2

= 0.1125 cm3

Number of circular discs made from cylinder = 50.625/0.1125 = 450

Hence the number of circular discs made from cylinder is 450.