Answer:
18
Explanation:
One trip around the gym would be 138 ft.
If we cut the diagonal, we use the Pythagorean theorem to find the distance of the hypotenuse, which is 51 ft.
One trip with the shortcut is 119 ft. (24 + 45 + 51 = 119).
Subtract 119 ft. from 138 feet and you have 18 ft. shorter route than walking the entire perimeter.