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 of the cylinder (r) = 3.5 cm

and height (h) = 7.5 cm

Total surface area = 2 $\pi$ r (h + r)

and curved surface area = $2\pi$ r h

$\therefore Ratio=\frac{2\pi r(h+r)}{2\pi rh}=\frac{h+r}{h}$

$=\frac{7.5+3.5}{7.5}=\frac{11}{7.5}=\frac{110}{75}=\frac{22}{15}$

$\therefore$ Ratio = 22 : 15