$\sqrt{15}$\sqrt{15}

$\displaystyle \frac{1}{2}$\displaystyle \frac{1}{2}

$\displaystyle \frac{7}{8}$\displaystyle \frac{7}{8}

$\displaystyle \frac{\sqrt{15}}{8}$\displaystyle \frac{\sqrt{15}}{8}