Question

Find the ratio between the total surface area of a cylinder to its curved surface area, given that its height and radius are 7.5 cm and 3.5 cm.

Answer 1

Radius (r) of cylinder = 3.5 cm
and height (h) = 7.5 cm
$\therefore$ Curved surface area =$2\pi rh$
and total surface area = $2\pi r(h+r)$
$\therefore$ Ratio= $2\pi r(h+r):2\pi rh$
$=(h+r):h=7.5+3.5:7.5\Rightarrow 11:7.5=\frac{11}{7.5}=\frac{11\times 2}{15}=\frac{22}{15}$
$\therefore$ Ratio $=22:15$