Question:
Height of a solid cylinder is 10 cm and diameter 8 cm. Two equal conical hole have been made from its both ends. If the diameter oaf the holes is 6 cm and height 4 cm, find
(i) volume of the cylinder,
(ii) volume of one conical hole,
(iii) volume of the remaining solid.
Solution:
Height = 10 cm.
Radius
$=\frac{8}{2}$
$=4 \mathrm{~cm} .$
(i) Volume of cylinder
$=\pi r^{2} h$
$=\pi \times(4)^{2} \times 10$
$=160 \pi \mathrm{cm}^{3}$
(ii) Volume of conical hole diameter of
cone = 6 cm.
radius $=\frac{6}{2}$
$=3 \mathrm{~cm}$
height $=4 \mathrm{~cm}$.
volume $=\frac{1}{3} \pi(7)^{2} h$
$=\frac{1}{3} \pi \cdot 9 \cdot 4$
$=12 \pi \mathrm{cm}^{3}$
(iii) Volume of remaining solid
$=160 \pi-2 \times(12 \pi)$
$=160 \pi-24 \pi$
$=136 \pi \mathrm{cm}^{3}$