Day 8 ­ The Pythagorean Theorem

Objectives:
1) Use of the Pythagorean Theorem
2) Use of the converse of the Pythagorean Theorem

1) Draw a right triangle represented with geometric squares as follows:


The sides of the right triangle have lengths 3, 4, and 5 units. The area of the larger square is equal to the total area of the two smaller squares.

This relationship is true for any right triangle

Have the students explore this concept with various size triangles to show this is true.

2) State the Pythagorean Theorem

Pythagorean Theorem: In a right triangle, the square of the length of the hypotenuse c is equal to the sum of the squares of the lengths of the legs a and b.

Symbols:

 

Practice Problem: Find the length of the hypotenuse of several right triangles.

 

3) Explain to the students the converse of the Pythagorean Theorem

Converse of the Pythagorean Theorem: If c is the measure of the longest side of a triangle, a and b are the lengths of the other two sides, and , then the triangle is a right triangle.

Have the students determine whether certain triangles are right triangles using the converse of the Pythagorean Theorem.

Practice Problem: The lengths of the three sides of a triangle are 5, 7, and 9 inches. Determine whether this triangle is a right triangle.

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