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In the proof of the Triangle Angle Sum Theorem, you must draw an auxiliary line. Which construction must you use to draw this line?

 Feb 28, 2019
 #1
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You need to draw a line through the apex point of the triangle that is parallel to the triangle's base

 

This shows how to do this :

 

http://www.mathopenref.com/printparallel.html

 

We can then use the fact that alternate interior angles are equal to complete the proof

 

cool cool cool

 Feb 28, 2019

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