HELP! URGENT!! PLEASE HELP ME!

The figure shows a representation of a football field. The units represent yards. A sports analyst marks the locations of the football from where it was thrown (point A) and where it was caught (point B). Complete the explanation for how you can use the Pythagorean Theorem to find the distance the ball was thrown. Then find the distance.

Create a right triangle with hypotenuse AB. The vertex at the right angle is either (30,) or ( ) and the lengths of the legs of the triangle are 21 yards and ( ) yards. The distance between A and B is about ( ) yards.