6-6 Solving Proportions

What does it mean to be proportional?

Your rates/ratios are equivalent!

An equation stating two ratios/rates are proportionalEx:

What is a proportion?

Checking proportionality:

Method #1: The cross products of any proportion are equal.

Method#2: The “fractions” are equivalent. You can check simplest form, common denominators, unit rates, etc.

Proportional?

Is 4 turns in 64 seconds proportional to 5 turns in 76 seconds?

Method #1

Method #2

Solving Proportions

Use cross products!

Is there another way we could have solved this one?

Solving Proportions

Word Problems

For every 18 people with a sore throat, there are 2 people who actually have strep. If 72 patients have a sore throat, how many probably have strep?