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 $\pi = \frac{22}{7}$?
Answer & explanation
Correct answer: option 1
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