Online Course Discussion Forum

P9 from week 2 day 2

 
 
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Re: P9 from week 2 day 2
by Dr. Kevin Wang - Monday, 10 August 2020, 1:03 AM
 

Try rotation: rotate the triangle ABC 60 degrees about point A to a new triangle ADC'.  Note that the segment AB becomes AD after rotation.  Now triangle ACC' is a big equilateral triangle.