Which equation is a proportion?

1/3 = 1/4

3/4=6/9

5/8=20/32

7/9=21/28

Well, 1/3 is equal to 0.3, and 1/4 is equal to. 25, so it can't be a.

3/4 is equal to. 75 and 6/9 is equal to 0.6, so it can't be b.

5/8 is equal to 0.625 and 20/32 is also equal to 0.625, so it could be c.

7/9 is equal to 0.7 and 21/28 is equal to 0.75, so it can't be D.

Your best bet is C. Because both sides of C are equal.

C 5/8=20/32