select all the pairs of ratios that form a proportion pick two

1/6, 4/20
7/9, 28/36
14/18, 21/27
30, 6/18

2. which pair of ratios does not form a proportion pick one

3/5, 24/40
30/10, 15/5
9/14, 3/4
7/12, 14/24

3.two shirts cost 12.50 how much will it cost to buy five of the shirts

6.25
31.25
25.00 this one
30.00