Question

The surface area of a sphere is 616 cm². Its radius is ______.

Options

• 7 cm

• 14 cm

• 21 cm

• 28 cm

Answer 1

The surface area of a sphere is 616 cm². Its radius is 7 cm.

Explanation:

Surface of a sphere = 616 cm² 

`therefore 4 pi "r"^2 = 616`

`=> 4 xx 22/7 xx "r"^2` = 616

`=> "r"^2 = (616 xx 7)/(4 xx 22)` = 49

`=> "r" = sqrt49` = 7 cm