Question

How do you find the circumference of a circle whose area is `60picm^2`?

Answer 1

`≈48.669" cm"`

Explanation:

We require to make use of the following `color(blue)"circle formulae"` for the area (A) and circumference (C) of a circle.

`color(orange)"Reminder " color(red)(bar(ul(|color(white)(2/2)color(black)(A=pir^2" and " C =2pir)color(white)(2/2)|)))`

Here A = `60pi`

`rArrpir^2=60pi`

divide both sides by `pi`

`(cancel(pi) r^2)/cancel(pi)=(60 cancel(pi))/cancel(pi)`

`rArrr^2=60rArrr=sqrt60`

Then `C=2pir=2pixxsqrt60≈48.669 " to 3 decimal places"`