Question

Find the surface area and total surface area of a hemisphere of radius $21cm$

• A. $2772{cm}^2$; $4158{cm}^2$
• B. $2442{cm}^2$; $4158{cm}^2$
• C. $2772{cm}^2$; $4874{cm}^2$
• D. $2112{cm}^2$; $4158{cm}^2$

Answer 1

The correct option is A $2772{cm}^2$; $4158{cm}^2$

Curved Surface area of a hemisphere $=2\pi r^2=2\times \frac{22}{7}\times 21\times 21=2772{cm}^2$

Total surface area of a hemisphere $=3\pi r^2=3\times \frac{22}{7}\times 21\times 21=4158{cm}^2$