Question

A hemispherical bowl is made of brass, $0.25cm$ thickness. The inner radius of the bowl is $5cm$. Find the ratio of outer surface area to inner surface area.

Answer 1

Given the radius of hemisphere bowl is $5$ cm and made by brass $0.25$ cm thickness

Then outer radius of hemisphere bowl $=5+0.25=5.25$ cm

Then surface area of inner surface of hemisphere $=4\pi r^2=4\times \pi \times (5{)}^2$

$=100\pi$

Then surface area of outer surface of hemisphere $=4\pi r^2=4\times \pi \times (5.25{)}^2$

$=110.25\pi$

Then ratio of outer and inner surface area $=\frac{110.25\pi }{100\pi }=\frac{110.25}{100}$