Question

Find the number of coins , each of radius 0.75 cm and thickness 0.2 cm, to be melted to make a right circular cylinder of height 8 cm and base radius 3 cm.

Answer 1

Given that,

Radius of each coin = 0.75 cm

Thickness = 0.2 cm

Height of circular cylinder = 8 cm

base radius =3 cm

We need to calculate the volume of cylinder

Using formula of volume

$V=\pi r^2h$

Put the value into the formula

$V=\pi\times3^2\times8$

$V_{cy}=226.19\ cm^3$

We need to calculate the volume of coin

Using formula of volume

$V_{c}=\pi\times r^2\times h$

Put the value into the formula

$V_{c}=\pi\times(0.75)^2\times0.2$

$V_{c}=0.353\ cm^3$

We need to calculate the number of coins

Using formula of number of coins

$N=\dfrac{volume\ of\ cylinder}{volume\ of\ coin}$

Put the value into the formula

$N=\dfrac{226.19}{0.353}$

$N=640$

Hence, The number of coins is 640.

Answer 2

Answer:

640 ✔️

Step-by-step explanation:

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Solution is in this pic.