Using the pythagorean theorem to prove if a triangle has a right angle or not would require you do what first? 1.find the altitude. 2.measure all mid-points 3.find the area 4.find side lengths

The correct answer is Choice 4.

The Pythagorean Theorem is about the relationships between the side lengths of a triangle. 

When a triangle is a right triangle the sides are in the form of: a^2 + b^2 = c^2

If you want to determine if a triangle is a right triangle, just plug the values into this equation and see if it is true.

Therefore, you should first know the sides lengths.