#### Answer

$110.4$

#### Work Step by Step

Recall, in part a we found:
$tan72^{\circ}=\frac{h}{3} \\ h = 3tan72^{\circ} =9.2 $
Thus, we find the volume of the pyramaid, which is equal to:
$V=(1/3)(A_{base})(h) = (1/3)(9.2)(6^2) = (1/3)(9.2)(36) = 110.4$