Although it is not disclosed in the post, from the context I can guess that AC and CB are the legs of the right-angled triangle ABC, while AB is its hypotenuse. Then, using the Pythagorean theorem, I can find the length of AB AB= = = 17 miles. Next, the problem asks how much longer is the path AC + CB than AB. To find it, subtract 17 from 8+15: (8+15) - 17 = 23 - 17 = 6. ANSWER. The path AC + CB is 6 miles longer than AB.