Triangle abc is a right triangle. if ac =7 and bc= 8 find ab. leave your answer in simplest radical form. a : b : c : d :

Use the Pythagorean Theorem: where  a  and  b  are the legs of the right triangle, and  c  is the hypotenuse (longest side!).

There is no picture provided with the problem, so it might be possible for the right angle to be at C and the hypotenuse is AB.  But that won't work with the answer choices given, because then

Now you know that the 7 must be a leg and 8 the hypotenuse.  Then .

By the way, it cannot be that 7 is the hypotenuse because it's the longest side and 8 is longer.