$\displaystyle \frac{2\sqrt{5}}{5}$\displaystyle \frac{2\sqrt{5}}{5}

$\displaystyle \frac{\sqrt{5}}{2}$\displaystyle \frac{\sqrt{5}}{2}

$2$2

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