60 discs each of diameter 21 cm and thickness $\frac{1}{3}$ cm are stacked one above the other to form right circular cylinder. What is its volume in $m^3$ if $\pi = \frac{22}{7}$?

$6.93 \times 10^{-3}$

We know that,

Volume of the cylinder = πr²h

We have,

The diameter of the disc = 21 cm

Then the radius = r = \(\frac{21}{2}\) cm

Height of 60 discs if they stacked one above the other = 60 × \(\frac{1}{3}\) = 20 cm

So,

Volume of the cylinder = \(\frac{22}{7}\) × \(\frac{21}{2}\) × \(\frac{21}{2}\) × 20 = 6930 cm³

As we know, 1 cm³ = 10^-6 m

6930 cm³ = 6.93 × 10^-3 m