Prove:
You can also prove triangles congruent by using two angles and a nonincluded side, as stated in the theorem below.
Theorem
If two angles and a nonincluded side of one triangle are congruent to two angles and the corresponding nonincluded side of another triangle, then the triangles are congruent.
If…
Then…
Proof of Theorem 4-2: Angle-Angle-Side Theorem
Given:
Prove:
You have seen and used three methods of proof in this book—two-column, paragraph, and flow proof. Each method is equally as valid as the others. Unless told otherwise, you can choose any of the three methods to write a proof. Just be sure your proof always presents logical reasoning with justification.