Answer:
Approximately 57
Explanation:
The Pythagorean theorem says that a^2+b^2=c^2, where a and b are the base and height, while c is the hypotenuse. 53^2+21^2=2809+441=3250. The square root of 3250 is 57.008771255, which rounded to the nearest tenth is 57. Hope this helped!