This Instructional Activity is a part of the Lesson 14, Unit 3, Grade 8. So far, you have seen two different proofs of the Pythagorean theorem. Consider an exercise in which students attempt to draw a triangle on graph paper that satisfies but is not a right triangle. Students should have access to rulers for this. Activities of this type may be sufficient to develop conceptual understanding of the converse; a formal proof by contradiction follows that may also be used.