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"proof" of the triangle sum theorem

Author:
Zawierucha, Duane Habecker
This applet shows that the sum of the interior angles for ANY triangle is 180°.

New Resources

  • Action/Consequence Parallel Lines and Angles
  • Triangle Midsegment Coordinate Proof
  • Artwork by Daniel Linus Torres
  • Coordinate Proofs for Parallelogram
  • Interior and Exterior Angle Sum of a Triangle

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  • Protractor Postulate (2)
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  • Perimeter
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  • Isosceles Triangles

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