Question

What is the length of BC in the right triangle below 21 and 72

Answer 1

Im guessing 21 and 72 are the side lengths for the triangle?

Alright, so since it's a right triangle you can use the Pythagorean theorem or a^2+b^2=c^2

Since i cant see the picture, im going to use some general math so i can figure out if those two sides are the legs or if one of them is the hypotenuse
Alright 
so im guessing the side we're trying to find is the hypotenuse

21^2+72^2=c^2
441+5184=c^2
5625=c^2
√5625=c
75=c

The answer is 75, hope i helped!