Question

A=pi r²,despeja r

a²=b²+c²-2b.x ,despejar x

Answer 1

A=pi r^2
A/pi=r^2
$r = \sqrt{ \frac{a}{\pi} }$
a^2=b^2+c^2-2bx
2bx=-a^2+b^2+c^2
$x = \frac{ { - a}^{2} + {b}^{2} + {c}^{2} }{2b}$