Proving Angle Relationships in Triangles

This video tutorial covers proving angle relationships in triangles using side-angle-side congruence and parallel lines. It explains the triangle angle-sum theorem, demonstrating that the sum of a triangle's interior angles is 180 degrees through a two-column proof. The video also proves the isosceles triangle theorem, showing that angles opposite congruent sides are congruent, using a model and two-column proof.

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