Question:
Tick (✓) the correct answer:
The ratio of the total surface area to the lateral surface area of a cylinder whose radius is 20 cm and height 60 cm, is
(a) 2 : 1
(b) 3 : 2
(c) 4 : 3
(d) 5 : 3
Solution:
(c) 4 : 3
Here,
$\frac{\text { Total surface area }}{\text { Lateral surface area }}=\frac{2 \pi r(h+r)}{2 \pi r h}$
$=\frac{h+r}{h}$
$=\frac{20+60}{60}$
$=\frac{4}{3}$
$=4: 3$