Question

The area of the circle whose diameter is 21 cm is ____________.

Options

• 346.5 cm²

• 37.68 cm²

• 18.84 cm²

• 19.84 cm²

Answer 1

The area of the circle whose diameter is 21 cm is 346.5 cm².

Explanation:

Here diameter = 21 cm

`therefore  "Radius r" = 21/2` cm

Area of the circle, A = `pi "r"^2`

`therefore "A" = 22/7 xx 21/2 xx 21/2`

`= 11 xx 3 xx 21/2`

`= 693/2`

`= 346.5  "cm"^2`