Question

Find the circumference of a circle whose area is 1386 cm².

Options

• 132 cm²

• 132 cm

• 42 cm

• 21 cm²

Answer 1

132 cm

Explanation

Area = πr²

Substituting the given area and π = 3.14

1386 = 3.14 × r²

`r^2 = 1386/3.14`

r² = 441

Take the square root of both sides to find r:

r = `sqrt441`

r = 21 cm

Circumference = 2πr

= 2 × 3.14 × 21

= 132 cm