Solve the equation M=5r2h7\displaystyle {M}=\frac{{{5}{r}^{{2}}{h}}}{{7}} for r\displaystyle {r} in terms of M\displaystyle {M} and h\displaystyle {h}. Assume r\displaystyle {r}, M\displaystyle {M} and h\displaystyle {h} are all positive.