Chapter 5

Ratios, Rates, and Proportions

Dorling Kindersley (DK) logo Real-World Snapshots

The model of the buildings in New York City is 1 over 20 of the actual size. In 2000, the population of New York City was about 9,314,000. Do you think the number of people per household in New York City was greater than or less than the U.S. average?

Data File

American Households

Year Number of Households Number of People/Household
1930 29,905,000 4.11
1940 34,949,000 3.67
1950 43,554,000 3.37
1960 52,799,000 3.33
1970 63,401,000 3.14
1980 80,776,000 2.76
1990 93,347,000 2.63
2000 105,480,000 2.59

SOURCE: U.S. Census Bureau. Go to for a data update. Web Code: abg-2041

You will use the data above in this chapter:

Dorling Kindersley (DK) logo

Real-World Snapshots On pages 286 and 287, you will solve problems involving scale models.


check mark Diagnosing Readiness

Where You've Been

  • In Chapter 3, you learned to simplify and compare fractions. You learned to express fractions as decimals.
  • In Chapter 4, you learned to add, subtract, multiply, and divide fractions and mixed numbers.

Where You're Going

  • In Chapter 5, you will write ratios and unit rates. You will solve proportions and find values in similar figures, maps, and scale models.
  • Applying what you learn, you will use a map to plan a trip. You will also find the scale of a model used by a special-effects artist.

Course 2 iText


Chapter 5
Ratios, Rates, and Proportions