Unit 8, Lesson 7
A Proof of the Pythagorean Theorem
Accelerated 7
Preparation
Lesson Narrative
In this lesson, students work through an area-based algebraic proof of the Pythagorean Theorem. This proof is based on two squares with the same area that are subdivided in different ways. By reasoning about the areas of both squares, students are able to see that (MP7).
An optional activity in this lesson works best when each student has access to a device that can run the applet, which allows students to experience a transformations-based proof without the additional preparation of paper manipulatives.
Students practice finding the unknown leg or hypotenuse given drawings or a written description.
- Calculate an unknown side length of a right triangle using the Pythagorean Theorem, and explain (orally) the reasoning.
- Explain (orally) an area-based algebraic proof of the Pythagorean Theorem.
- Label the “legs” and “hypotenuse” on a diagram of a right triangle.
Let's prove the Pythagorean Theorem.
Required Materials
Activity 3
Required Preparation
For the digital version of the activity, acquire devices that can run the applet.