A=πr√(h^2-r^2) make "r" the

Question

subject of the formula

show workings
#thanks

Answer 1

A=πr√(h^2-r^2)
A/π=r√(h^2-r^2)
(A/π)^2=r(h^2-r^2)

are my step right?, please help me from here. Thanks

Answer 2

(A/pi)^2 = r^2 (h^2-r^2)
=-r^4+h^2r^2

r^4 - h^2 r^2 + (A/pi)^2 = 0

r^2 = [h^2 +/-sqrt(h^4-4A^2/pi^2)]/2

r = sqrt { [h^2 +/-sqrt(h^4-4A^2/pi^2)]/2 }