A triangle is called a right triangle if one of its angles is 90°. The Pythagorean theorem is an equation that can be used to calculate the missing side length in a right triangle. In this type of vector addition,
the magnitude of the resultant is the hypotenuse of a right triangle.
The hypotenuse, R, of a right triangle is the side of the triangle opposite the 90° angle. The angle
opposite side A is a, and the angle opposite side B is b. The Pythagorean theorem states that
RP = A2 + B2. For example, if A= 3.0 cm and B = 4.0 cm, the length of R can be found by using the
Pythagorean theorem.