Prealgebra for Two-Year Colleges/Workbook AIE/Measuring distances

Measuring Distances

Materials Needed: Ruler marked in inches and cm, string, scissors to cut the string

Why

When you are given a map, blueprint, or diagram, you often need to measure with a ruler to get the information you need to solve the problem.

Learning Objectives

Use a ruler to measure perimeters (whole numbers of inches and cm).
Use a string and a ruler to measure paths that are not straight (whole numbers of inches).

Warm-up

1. Explain how to calculate the perimeter of an object.

Add up the lengths of all the sides.

2. Which of the following objects can be used to help you measure perimeter? How?

- Measuring cup
- Graph paper
- Ruler
- 3”×5” index card
- String
- Sand

Activity

1. Without measuring, decide which of the following shapes has the larger perimeter. Explain your reasoning.

2. Use a ruler to measure the perimeter of the rectangle in inches.

3. Use a ruler to measure the perimeter of the “H” figure in centimeters.

4. Use a ruler to measure the perimeter of the triangle in inches.

5. Use a piece of string and a ruler to measure the perimeter of the oval in inches.

6. Use a piece of string and a ruler to measure the length of the curved path in inches.

7. Use a piece of string and a ruler to measure the shortest path on the map along the highways from the bull’s eye in Antioch to the bull’s eye in Oakland in inches.

4 inches, to the nearest whole inch

8. If each inch on the map represents 10 miles in real life, then how far is it between the spots represented by the bull’s eyes?

40 miles