Is a triangle with side lengths of 4mm,11mm and 15 mm a right triangle? Explain

Question

Is a triangle with side lengths of 4mm,11mm and 15 mm a right triangle? Explain

Answer 1

Remember that a right triangle needs to follow the Pythagorean theorem, that is,

a² + b² = c²

where c is the length of the hypotenuse and a and b are the lengths of the other sides of the right triangle.  We can check to see if this property holds for the given triangle.  Since 

4² + 11² = 137 =/= 15²

the Pythagorean theorem does not hold for the given triangle, meaning that it can not be a right triangle.