Lesson: Pythagorean Inequality Theorem Mathematics • 8th Grade

In this lesson, we will learn how to determine whether an angle in a triangle is acute, right, or obtuse by using the Pythagorean inequality theorem.

Lesson Plan

Students will be able to

understand that in a triangle with vertices , , and , if
- , then is a right angle,
- , then is an obtuse angle,
- , then is an acute angle,
determine the type of a triangle (acute, right, or obtuse) by using the Pythagorean inequality theorem, which involves identifying first the greatest angle in the triangle given its side lengths,
solve geometry problems using the Pythagorean inequality theorem.

Q1:

In triangle , . What type of angle is ?

Q2:

In triangle , . What type of angle is ?

Q3:

In a triangle , if , which angle is the right angle?