How to find proportions

By: deonta brown

What a proportion is

• A proportion is simply a statement that two ratios are equal. The following proportion is read as "twenty is to twenty-five as four is to five.“

20

25 4

5

How to start it

•It can be written in two ways: as two equal fractions a/b = c/d; or using a colon, a:b = c:d

a

b

c

d

Step 1

•The following proportion is read as "twenty is to twenty-five as four is to five.“

20

25

4

5

Step 2

•cross products of a proportion, we multiply the outer terms and the middle terms

Step 2

•Here, 20 and 5 and 25 and 4 Since the cross products are both equal to one hundred, we know that these ratios are equal and that this is a true proportion.

• 20x5=25x4

• cross products 100=100

20

25

4

5