Hey, we are doing a review but I forgot how to set up proportions. Please help me!!

It can be written in two ways: as two equal fractions a/b = c/d; or using a colon, a:b = c:d. The following proportion is read as "twenty is to twenty-five as four is to five." In problems involving proportions, we can use cross products to test whether two ratios are equal and form a proportion.

20/25 = 4/5

20 x 5 = 25 x 4

100 = 100