when we talk about right triangles they must fulfill the pythagorean theorem, which stand that
[tex]a^2+b^2=c^2[/tex]
in which c must be the longest side of the triangle.
chech if this is true with the side lenghts given
[tex]3^2+4^2=5^2[/tex]
simplify the expression
[tex]\begin{gathered} 9+16=25 \\ 25=25 \end{gathered}[/tex]
in this case yes it is a right triangle because the pythagorean theorem applies
