Proportions

A proportion is a

• ratio statement

• an "if-then" statement

• a statement of 2 ratios

• a comparison

A ratio is

• comparing a bunch of numbers

• a comparison between 2 quantities

• an estimation of an amount

• a variable

All of the following are proper representations of a ratio EXCEPT

• a/b

• a to b

• a:b

• a over b

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

• Cross multiply

• Divide everything

• Get rid of variables

• Guess

If the ratio of boys to girls in a class is 3:4, how many boys are there if there are 20 girls?

• 15

• 25

• 10

• 30

• 4

• 6

• 8

• 10

What is the constant of proportionality?

• $3

• $4

• $2

• $9

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)

Sandra wants to give a party for 60 people. She has a punch recipe that makes 2 gallons of punch and serves 15 people. How many gallons of punch should she make for her party?