# Lesson 12: Using a Trundle Wheel to Measure Distances

Let’s use our trundle wheels.

## 12.1: Measuring Distances with the Trundle Wheel

In the previous lesson, you made trundle wheels so that you can measure walking distances. Today, you’ll try them out and see how well they work.

If you do not have a trundle wheel, you can use an applet to simulate measuring. Your teacher will tell you a path whose distance you will measure. Measure the distance with a trundle wheel three times. Decide how to report the distance to the class. Be prepared to explain the reasons for your choice. Record:

diameter number of rotations computation distance
row 1 trial 1
row 2 trial 2
row 3 trial 3
• Distance to report to class:

1. Compare your results with the results of two other groups.

2. Express the differences between the measurements of the three groups in terms of percentages.

3. Discuss the advantages and disadvantages of the different measurement methods.

To use the applet:

• Choose a diameter for the wheel, and enter a number 1 -- 5 for the path you will measure.
• Watch carefully to keep track of the number of rotations that the wheel makes before it stops.
• Try three different diameters for the same path, and compare your results.
• Answer the questions.

GeoGebra Applet gDkZ6Yjy