Question 255740
The perimeter of a circle, also circumference is
(i) {{{C = 2*pi*r}}}
The area of a circle is
(ii) {{{A = pi*r^2}}}
solve the area formula for r and we get
(iii) {{{a/pi = r^2}}}
(iv) {{{sqrt(A/pi) = r}}}
substitute (iv) into (i) to get
{{{C = 2*pi*sqrt(A/pi)}}}
which is simplified to
{{{C = 2sqrt(A*(pi))}}}