To know if a triangle is a right-angled triangle from the sides given, we use the Pythagoras theorem to test it.
The theorem states that the sum of the squares of two sides is equal to the square of the longest side (hypotenuse)
[tex]\begin{gathered} 4^2+5^2=16+25=41 \\ 7^2=49 \\ S\text{ince } \\ 4^2+5^2\ne7^2,\text{ then the triangle is not a right triangle} \end{gathered}[/tex]Therefore, a triangle with length of sides 4m, 5m and 7m is not a right triangle.
