Aright triangle. if ac = 7 and bc = 8, find ab. leave your answer in simplest radical form.

We don't know whether those two sides are both legs
of the right triangle, or if  BC  is the hypotenuse.

If  AC  and  BC  are both legs, then

           AB = √ (AC² + BC²)
                 =  √ (7² + 8²)
                 =  √ (49 + 64)  =  √ 113 .

If  BC  is the hypotenuse of the right triangle, then

           AB = √ (BC² - AC²)
                 =  √ (8² - 7²)
                 =  √ (64 - 49)  =  √ 15 .