Unit 7 · Right Triangles and Trigonometry

7.2Converse of the Pythagorean Theorem

Quick Answer

Converse: if a² + b² = c², the triangle is right. If a² + b² > c², it is acute. If a² + b² < c², it is obtuse. Use the longest side as c when testing.

Essential Question

How can you classify a triangle as right, acute, or obtuse using only its side lengths?

Learning Goals

  • 1State the Converse of the Pythagorean Theorem.
  • 2Classify triangles as right, acute, or obtuse given side lengths.
  • 3Determine whether three lengths form a right triangle.

Key Vocabulary

Converse of the Pythagorean Theorem

If a² + b² = c², then the triangle is a right triangle.

Pythagorean triple

A set of three positive integers that satisfy a² + b² = c², e.g. 3-4-5.

Full lesson content coming soon

Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.