Since it is a right triangle, we can use pythagorean theorem:
[tex]\begin{gathered} c^2=a^2+b^2 \\ where \\ c>a,c>b \\ Let \\ c=8.5m \\ b=7.5m \end{gathered}[/tex]
So:
[tex]\begin{gathered} 8.5^2=a^2+7.5^2 \\ a=\sqrt[]{8.5^2-7.5^2} \\ a=\sqrt[]{72.25-56.25} \\ a=\sqrt[]{16} \\ a=4m \end{gathered}[/tex]
