Answer
$\$5,446.38$
Work Step by Step
By Heron's formula,
$K=\sqrt{s(s-a)(s-b)(s-c)}$, where $s=\frac{a+b+c}{2}.$
Hence, here
$s=\frac{100+50+75}{2}=112.5$
Thus,
$K=\sqrt{112.5(112.5-100)(112.5-50)(112.5-75)}\approx1815.46.$
The unit price is $3$ dollars per square foot. Multiply the area and the cost per square foot to obtain:
Total cost = $\$3(1815.46)=\$5,446.38$
