Do the ratios 8/12 and 2/3 form a proportion

Answer 1

Set them equal to one another, then cross multiply. After cross multiplying, if the left side equals the right side, then they form a proportion. If not, they don't. For example, consider 1/2 and 5/10:

1/2 = 5/10

Cross multiply:

1·10 = 5·2

10 = 10

So 1/2 and 5/10 form a proportion. Now consider 6/12 and 7/15:

6/12 = 7/15

Cross multiply:

6·15 = 7·12

90 = 84

S0 6/12 and 7/15 do NOT form a proportion. Now try it on 8/12 and 2/3.