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Investigating Pythagorean Theorem

WARM-UP

In the Geogebra activity above, a very special right angled triangle is shown. It has side lengths 3, 4 and 5. A set of three whole number side lengths that satisfies Pythagoreans Theorem like this are called Pythagorean Triples. Use the activity to move the two orange points to create different triangles. Find as many Pythagorean Triples as you can and list them in the text box below.

Review your findings from the previous question. Did you notice any interesting relationships between your sets of Pythagorean Triples? If so, explain your findings below.

TODAY'S LESSON

Move the blue point to make new examples

What is a vocabulary word that describes the relationship between the four green triangles? Explain how you know your answer is true. (Hint: What theorem can you use?)

What types of triangles are the four green triangles?

Why is the pink space a square?

Write an expression for the area of the pink square in terms of c.

Move the blue point where you like. Think of the triangles covering some of the area of the red square and the pink square covering the rest. Transform the triangles by moving the Transform slider to the right. The pink space now appears as two squares, but the total area is the same as the area of the original pink square before the transformation.

Write an expression for the area of the upper pink square in terms of a.

Write an expression for the area of the lower pink square in terms of b.

Write an expression for the total area of the pink space in terms of a and b.

Observe the animation a few more times by moving the slider from the left to the right. Would you say that pink area becomes larger, smaller, or remains equal as you move the slider from left to right?

Select all that apply
  • A
  • B
  • C
Check my answer (3)

Express your answer from the previous question as an equation. (Hint: What were the area functions you found earlier?)

The Pythagorean Theorem states that the side lengths of a right triangle are related by the equation a2 + b2 = c2, where a and b are legs and c is the hypotenuse. Did this inductive reasoning activity help convince you about the truth of the Pythagorean Theorem? Explain.

INFORMATIVE ASSESSMENT

Click on Toolbar Image tool, then click the Toolbar Image tool to write on the following modules. Write your work on the modules as you solve the problems below.

Enter the value you found for the missing side below. (Hint: Look at the missing side. Is it a LEG or the HYPOTENUSE?)

Enter the value you found for the missing side below. (Hint: Look at the missing side. Is it a LEG or the HYPOTENUSE?)