Ratios

1
Ratios Rates of Change

• Chapter 11, Section 2, 3, 4

2
Ratio

• A ratio is a comparison of like or unlike
  quantities.
• It can compare a part to a part, a part to a
  whole, or the whole to a part.
• Does this sound like something else we have
  studied about?
• A FRACTION
• This can be written as a fraction (3/9) or 3 to 9
  or 39.

3
Practice

• Lets write a ratio of the number of people with
  blond hair to the number of people with black
  hair.
• Boys to girls
• Basketball players to non basketball players

4
Equal Ratios

• We can find equal ratios that show the same
  comparison.
• For the ratio 1824
• 18
• 24

5
Rates

• A rate is a ratio that compares unlike units.
• A common rate is miles per hour.
• If the comparison is to one unit, it is called a
  unit rate.
• Example Give the unit rate for 22 laps in 5
  minutes.
• 22 laps laps
• 5 minutes 1 minute

6
Practice

• Write each rate as a unit rate.
• 15 books in 3 weeks
• 8 visits in 5 days

7
Constant or Vary

• What does constant mean?
• What does vary mean?
• Constant-to stay the same
• Vary-to change