Question

The circumference of a circle whose area is 81π2 is

Answer 1

Answer:

Given area of a circle is 81π.

We know formula for area of a circle is πr

2

So,πr

2

=81π

⇒r

2

=81

⇒r=9

Formula for circumference is 2πr.

So putting r=9 circumference will be

2π9=18π