How do you calculate circumference from area

use the formula of a circle or pi times radius r squared = Area then use the formula for the circumfrence of a circle which is two times pi time radius r = circumfrence then isolate r in the formula (for area)

sqrt (A/pi) then multiply the raduis r by 2*pi to get the circumference

C = 2*pi*sqrt (A/pi)

See below

Step-by-step explanation:

Given the area A you can find the radius of a circle.

A = πr^2

so r^2 = A / π

and r = the positive square root of A/π.

Having found the radius r you can calculate the circumference C using

C = 2πr.