We have the following:
In a right triangle, the longest side belongs to the hypotenuse, therefore
[tex]\begin{gathered} c^2=a^2+b^2 \\ a=84 \\ b=13 \\ c=85 \end{gathered}[/tex]
replacing:
[tex]\begin{gathered} 85^2=84^2+13^2 \\ 7225=7225 \end{gathered}[/tex]
Therefore, if it is a right triangle
