$\begin{array}{1 1}(a)\;a=\large\frac{6}{7},\normalsize b=\large\frac{4\sqrt{3}}{5}\\(b)\;a=\large\frac{5}{2},\normalsize b=\large\frac{5\sqrt{3}}{2}\\(c)\;a=\large\frac{7}{5},\normalsize b=\large\frac{5\sqrt{7}}{2}\\(d)\;\text{None of these}\end{array}$
