Answer: S=6√6 m².
Step-by-step explanation:
Heron's formula
[tex]\displaystyle\\\boxed {S=\sqrt{p*(p-a)(p-b)(p-c)} }[/tex],
a, b, c - sides of a triangle,
[tex]\displaystyle\\p=\frac{a+b+c}{2}[/tex]
S - triangle area.
a=7 m, b=5 m, c=6 m.
[tex]p=\frac{7+5+6}{2} \\p=\frac{18}{2} \\p=9 (m).[/tex]
Hence,
[tex]S=\sqrt{9*(9-7)*(9-5)*(9-6)}\\S=3*\sqrt{2*4*3}\\S=3*2*\sqrt{2*3} \\S=6\sqrt{6} \ (m^2).[/tex]