Question:
The curved surface are of a cylinder is 1760 cm2 and its base radius is 14 cm. The height of the cylinder is
(a) 10 cm
(b) 15 cm
(c) 20 cm
(d) 40 cm
Solution:
(c) 20 cm
Curved surface area of the cylinder $=2 \pi r h$
$=2 \times \frac{22}{7} \times 14 \times h$
Therefore,
$2 \times \frac{22}{7} \times 14 \times h=1760$
$\Rightarrow h=\frac{1760}{88} \mathrm{~cm}$
$\Rightarrow h=20 \mathrm{~cm}$
Hence, the height of the cylinder is 20 cm.