All you have to do is divide 72 by 90n and it will give you .8, move the decimal two places to the right to give you 80 and subtract 80 from 100 to get 20
1, 3, 5, 7. 1 and 3 they are vertical meaning they are congruent. 3 and 5 are alternate interior angles meaning they are congruent. 7 and 5 are vertical so they are congruent.
