Question

450 coins of thickness 0.2cm are melted to form right circular cylinder of height 10cm and diameter 4.5cm. find diameter of coin​

Answer 1

Step-by-step explanation:

Dia of coin =1.5 cm

Radius of coin =1.52 cm=0.75 cm

Thickness of coin = height of coin =0.2 cm

Dia of required right circular cylinder =4.5 cm

Radius of required right circular cylinder =4.52 cm=2.25 cm

We know that the volume of cylinder is given by V=πr2h

As the coins are in the form of thin cylinder

Volume of each coin =π×(0.75)2×0.2=0.1125π cm3

Volume of required right circular cylinder =π×(2.25)2×10=50.625π cm3

Number of coin required =(volume of required right circular cylinder)(volume of each coin)

=50.625π0.1125π=450 coins