Unit 5, Lesson 10
How Well Can You Measure?
Accelerated 6
Preparation
Lesson Narrative
In this lesson, students apply what they have learned about proportional relationships to investigate squares. They measure squares of various sizes and use tables and graphs to analyze the measurements (MP8).
First, students see that there is a proportional relationship between the length of a square’s diagonal and its perimeter, even though measurement error makes it difficult to identify the exact constant of proportionality. As students make assumptions and approximations to simplify a situation, they are modeling with mathematics (MP4). Next, students see that even taking measurement error into account, the relationship between the length of the diagonal and the area of a square is not a proportional relationship.
- Create and describe (in writing) graphs that show measurements of squares.
- Justify (orally and in writing) whether the relationship shown on a graph is close enough to a straight line through the origin that it might be a proportional relationship with some measurement error.
- Recognize that when we measure the quantities in a proportional relationship, measurement error can cause the graph to be not perfectly straight and the quotients to be not exactly constant.
Let’s see how accurately we can measure.
Required Preparation
For the digital version of the activity, acquire devices that can run the applet.