Pythagorean Theorem Differentiated Instruction for Use in an ...

Day 4
Lesson – Identifying Right Triangles
Objectives
Students will be able to:
identify the legs and hypotenuse of a right triangle
state the Pythagorean Theorem
use the Pythagorean Theorem to determine if a triangle is a right triangle
Materials:
Calculator, string, tape, copies of practice 8-6 from workbook
Outline of Activities:
1. Go over the homework problems. Use this as an opportunity to review how to use the
Pythagorean Theorem to find missing side lengths.
2. Review right triangle vocabulary and the formula for the Pythagorean Theorem. Ask students, if
the side lengths of a triangle do not reflect the Pythagorean Theorem, does this mean that the
triangle is not a right triangle?
3. Students should begin ancient Egyptian surveying activity. It may be necessary to demonstrate
how to divide the string into twelve equal sections. Fold string in half, fold haves in half, divide
quarters into thirds by trial and error. Have a student demonstrate the solution on the overhead.
Ask students again, if the side lengths of a triangle do not reflect the Pythagorean Theorem, does
this mean that the triangle is not a right triangle?
4. Demonstrate using the Pythagorean Theorem to identify a non-right triangle. Is a triangle with
sides 7, 25, 20 a right triangle? Use the Pythagorean Theorem a² + b² = c². Is 7² + 20² = 25² ? 49
+ 400 ≠ 625 This triangle is not a right triangle. Is a triangle with sides 5, 15, 30 a right triangle?
Use the Pythagorean Theorem a² + b² = c². Is 5² + 15² = 18² ? 25 + 225 ≠ 324 This triangle is not
a right triangle.
5. Write the following side lengths on the board and have students determine whether or not the
triangles are right triangles. Which of these triangles are right triangles? 12,16,20 right triangle
8,15,17 right triangle 12,9,16 not a right triangle 4,7,8 not a right triangle 9,8,12 not a right
triangle 20,21,29 right triangle Use this as an opportunity to work with students who are having
difficulties.
6. Summarize Pythagorean Theorem Unit. Ask students to identify the legs and hypotenuse of a
right triangle. Ask students for the formula for the Pythagorean Theorem. Ask students how the
Pythagorean Theorem can be used.
Assign students additional activities as needed.
Homework:
Practice 8-6 Exploring the Pythagorean Theorem form workbook.
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