Ratios and Proportions

Proportions & Ratios

Dr. Tom Giles

Proportions and Ratios

What is a proportion?

• A proportion is an equation that states that two ratios (fractions) are equal.

• Example: A rope's length and weight are in proportion.

  When 20m of rope weighs 1kg, then: 40m of that rope weighs 2kg

  
  

Working with Proportions

Multiple Choice

Solve the proportion.

• k=5

• k=3.3333333

• k=60

• k=90

Multiple Choice

At HEB 3 pounds of hamburger meat is on sale for $6. If Alicia buys 10 pounds of hamburger, how much will she pay?

• $30

• $20

• $60

• $10

Multiple Choice

In your class 6 students out of 30 students are left-handed. What percent of students are left-handed?

• 18%
• 20%
• 5%
• 60%

Multiple Choice

Solve the proportion below:

• 42
• 6
• 2
• 28

Multiple Choice

Solve the proportion below:

• 3
• 24
• 21
• 12

Ratios

• A ratio states how much of one thing there is compared to another.

• Ratios can be shown 3 ways:

• 3 to 1

• 3:1

• 3/1

Ratios

Multiple Choice

A recipe that makes 6 servings calls for 2 eggs. If you use 3 eggs and adjust all of the ingredients proportionally, how many servings will the new recipe make?

• 3

• 6

• 9

• 10

• 12

Multiple Choice

Andrew has 2 cats and 9 fish. He writes the ratio 2:11. What type of ratio did he write?

• Part-to-part

• Unit rate

• Part-to-whole

• Whole-to-part

Multiple Choice

What are the three different ways you can write a ratio?

• Fraction, comma, words

• Fraction, colon, words

• Colon, words, pictures

• Picture, fraction, comma

Multiple Choice

Mary lost 3 out of 5 games. What is the ratio of games Mary lost to the games she won?

• 3/5

• 2/5

• 3/2

• 5/2

Multiple Choice

At the candystore, for every 2 suckers you buy, you get 1 free, if billy bought 14 suckers how many free ones will he get

• 16

• 14

• 7

• 28

Multiple Choice

Solve.

• 5

• 9

• 18

• 43

Multiple Choice

 Solve.

• 60
• 24
• 16
• 12

Multiple Choice

Write a proportion and solve.

• 3 tablespoons
• 4 tablespoons
• 9 tablespoons
• 12 tablespoons

Multiple Choice

Write a proportion and solve.

• 10 meters
• 15 meters
• 22.5 meters
• 30 meters

Multiple Choice

Write a proportion and solve.

• .114 kilometers
• 107 kilometers
• 285 kilometers
• 613 kilometers

Multiple Choice

Steve won his election for student body president by a margin of 7 to 2.  His opponent had 3,492 votes.  How many votes did Steve have?

• 998 votes
• 12,222 votes
• 997 votes
• 1,222 votes

Multiple Choice

How much did Tom pay in income tax on a gross income of $50,000 if 9% of his income was taxed?

• $55,555
• $4000
• $5,555
• $4,500

Multiple Choice

A football team plays 25 games and wins 32% of them.  How many games does the team win?

• 17 games
• 10 games
• 8 games
• 13 games

Multiple Choice

Finks jewelry company bought 800 bracelets for $450.  How much did each bracelet cost the company?

• $1.78
• 50 cents
• 78 cents
• 56 cents

Multiple Choice

A test has 60 questions. Franco answers 75% of them correctly.  How many did he answer correctly?

• 45 Correct

• 48 Correct

• 54 Correct

• 35 Correct