Question

A hemispherical bowl is made of steel, $0.25cm$ thick. The inner radius of the bowl is $5cm$. Find the outer curved surface area of the bowl.

• A. $173{cm}^2$
• B. $133{cm}^2$
• C. $143{cm}^2$
• D. $273{cm}^2$

Answer 1

Answer: (A)

$173{cm}^2$

$r=5cm$, thickness of steel sheet $=0.25cm$

$\Rightarrow$ $R=5cm+0.25cm=5.25cm$

outer curved surface area of the bowl $=2\pi R^2$

$=2\times \frac{22}{7}\times \frac{525}{100}\times \frac{525}{100}{cm}^2=173.25{cm}^2$