Question

If the curved surface area of a cylinder is 1760 cm² and its base radius is 14 cm, then its height is
(a) 10 cm
(b) 15 cm
(c) 20 cm
(d) 40 cm

Answer 1

(c) 20 cm

Curved surface area = 1760 cm²
Suppose that h cm is the height of the cylinder.
Then we have:
$$\begin{gathered} 2\mathrm{\pi r}h=1760 \\ \Rightarrow 2\times \frac{22}{7}\times 14\times h\mathit{}=1760 \\ \Rightarrow h=\frac{1760\times 7}{44\times 14}=20\mathrm{cm} \end{gathered}$$