Answer: 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.