what is used to determine the unknown side length of a right triangle
By Mary Jane Sterling from Trigonometry For Dummies, 2nd Edition. The Pythagorean theorem states that a 2 + b 2 = c 2 in a right triangle where c is the longest side. You can use this equation to figure out the length of one side if you have the lengths of the other two.The figure shows two right triangles that are each missing one side's measure.he length of the missing side, c, which is the hypotenuse, is 50. The triangle on the right is missing the bottom length, but you do have the length of the hypotenuse. It doesn't matter whether you call the missing length a or b. Replace the variables in the theorem with the values of the known sides.