Question:
Find the (i) curved surface area (ii) total surface area and (iii) volume of a right circular cylinder whose height is 15 cm and the radius of the base is 7 cm.
Solution:
Given :
Height, $h=15 \mathrm{~cm}$
Radius, $r=7 \mathrm{~cm}$
(i) Curved surface area, $S_{1}=2 \pi r h$
$=2 \times \frac{22}{7} \times 7 \times 15$
$=660 \mathrm{~cm}^{2}$
(ii) Total surface area, $S_{2}=2 \pi r(r+h)$
$=2 \times \frac{22}{7} \times 7 \times(7+15)$
$=44 \times 22$
$=968 \mathrm{~cm}^{2}$
(iii) Volume of the right circular cylinder, $V=\pi r^{2} h$
$=\frac{22}{7} \times 7^{2} \times 15$
$=2310 \mathrm{~cm}^{3}$