Rewrite the proportion 7:21 = 3:9 as a proportion using fractions.

1/3 ig

Answer: In this problem you want to rewrite the proportion 7:21 to 3:9.

First, a proportion is a relation between two quantities, this is if the proportion of A to B is 7:21, then you can represent it in a equation as:

7*A = 21*B

If you divide by the same number in both sides of the equation, you dont affect the equality, then if i divide both sides by 7, the equation turns into:

7*A/7 = 21*B/7

A = (21/7) * B = 3*B

Now if i multiply both sides by 3.

3*A = 3 * (3*B) = 9*B

3A = 9*B

so now the proportion is 3:9.

Also, if you want to see if two proportions are equivalent, you need to see that quotients are the equal.

In this case 21/7 = 3, and 9/3 = 3.