\(a\,=\,b\,*\,\frac{c^2}{d^2} \\~\\ a\,=\,\frac{bc^2}{d^2}\)

Multiply both sides of the equation by d^{2} .

\(ad^2\,=\,bc^2\)

Divide both sides of the equation by a .

\(d^2\,=\,\frac{bc^2}{a}\)

Take the ± square root of both sides.

\(d\,=\,\pm\sqrt{\frac{bc^2}{a}}\)