Answer :
[tex]\bf \textit{Heron's Area Formula}\\\\
A=\sqrt{s(s-a)(s-b)(s-c)}\qquad
\begin{cases}
a=6.2\\
b=7.5\\
c=4.9\\\\
s=\frac{a+b+c}{2}\\
\qquad 9.3
\end{cases}
\\\\\\
A=\sqrt{9.3(9.3-6.2)(9.3-7.5)(9.3-4.9)}
\\\\\\
A=\sqrt{9.3(3.1)(1.8)(4.4)}\implies A=\sqrt{228.3336}
\\\\\\
A\approx 15.11071143262[/tex]