$\displaystyle \frac{9}{2}$\displaystyle \frac{9}{2}

$\displaystyle \frac{9\sqrt{3}}{4}$\displaystyle \frac{9\sqrt{3}}{4}

$\displaystyle \frac{9\sqrt{3}}{2}$\displaystyle \frac{9\sqrt{3}}{2}

$6$6