Sal took four quizzes this grading period in Algebra II. He made a 56/72, 28/32, 70/90, and 42/56. Which two grades are equivalent?

56/72 can be simplified to 14/18, then to 7/9 * dividing by 4, then by 2*

28/32 can be simplified to 7/8 * dividing by 4*

70/90 can be simplified to 7/9 * dividing by 10*

7/9 and 7/9 are equivalent, so 56/72 and 70/90 are equivalent.