Question 969951
Pythagorean Theorem formula.  If truth for any combination of sides, then this is a right triangle.  


Best way to arrange the numbers for the sides is to use the longest side length for one member of the equation and the other two side lengths for the other member.  The hypotenuse of a right triangle is the triangle's longest side.  If longest side squared is greater than sum of squares of the other two sides, then this triangle has an obtuse angle.