Ratios & Proportions

A ratio is

• comparing a bunch of numbers

• a comparison between 2 quantities

• an estimation of an amount

• a variable

A proportion is a

• ratio statement

• an "if-then" statement

• a statement of 2 ratios

• a comparison

All of the following are proper representations of a ratio EXCEPT

• a/b

• a to b

• a:b

• a and b

To solve for missing info in a proportion statement you must first

• Cross multiply

• Divide everything

• Get rid of variables

• Guess

Two out of every 3 students in Mr. Pearson’s ninth grade class recycle aluminum cans. If 48 students recycle aluminum cans, HOW MANY STUDENTS are in Mr. Pearson’s class?

Cindy’s job is to check computer printers for defects. Out of 420 printers she has to check, only 3 of the first 84 have been defective. Using this information, what is the best prediction of the TOTAL NUMBER OF DEFECTIVE PRINTERS?(Set up your ratio)

If a class has 14 redheads, 8 brunettes, and 6 blondes- What is the REDUCED ratio of redheads to brunettes?

• 4:7

• 14:8

• 8:14

• 7:4