What is a ratio that compares a number to 100

Percent

Step-by-step explanation: A percent is a ratio that compares a number to 100.

Let's look at the ratio 37 to 100. This ratio can be written as 37%.

It should make since that the word "percent" is related to the number 100 since there are 100 cents in a dollar and 100 years in a century. All of these words percent, cents, and century come from the latin root cent meaning 100.