Answer
$27.81$ square units
Work Step by Step
By Heron's formula, the area $K$ is given as
$K=\sqrt{s(s-a)(s-b)(s-c)}$, where $s=\frac{a+b+c}{2}$
Hence here $s=\frac{7+8+10}{2}=12.5$,
$K=\sqrt{12.5(12.5-7)(12.5-8)(12.5-10)}\\$
$K\approx27.81$ square units
