5-3 Proportions

Lesson Link: Tell if each pair of ratios are equivalent. Write yes or no and explain.

a.) b.)

c.)d.)

Create two different proportions using

= =

A proportion is a statement that shows two ratios are equal, or proportional.

Proportions can be written in numbers or in words.

"One is to two as three is to six."

First Method: Rewrite the ratios in lowest terms and see if they are equivalent.

1.)

=

=

2.) Decide if and are proportional

=

=

Second Method: Use related multiplication to test proportionality

1.) 2.)

Third Method: Use cross products (diagonal multiplication) to test proportionality

1.) 2.)

Real-life problem: Researchers tracking a pod (group) of killer whales found that the whales swam 30 miles in 4 hours on Monday and 64 miles in 8 hours on Tuesday. Are these rates proportional? Use all three methods to test proportionality.

lowest termsrelated

multiplicationcross products

Demonstrate Understanding: Determine whether the ratios form a proportion. You may use a calculator, but must show work.

1.) 2.)

3.) 4.)

5.) 6.)