Question

The area of a circle is 38.5 cm². The circumference of the circle is

विकल्प

• 6.2 cm

• 12.1 cm

• 11 cm

• 22 cm

Answer 1

22 cm

Let the radius be r cm.

We know:

Area of a circle

=  πr² cm² 

Thus, we have 

πr2 = 38.5

`=>22/7xx"r"^2 = 38.5`

`⇒ r^2 = (38.5xx7/22)`

`=> "r"^2 = (385/10xx7/22)`

`=> "r"^2 = 49/4`

`=> r = 7/2`

Now,
Circumference of the circle = 2πr

`= 2 × 22/7xx"r"`

`=(2xx22/7xx7/2)`

= 22 cm