November 27th, 2017, 11:34 AM  #21 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038 
What's your point Manus? Those are all "givens". Like it is given that angleADB = 70; so automatically ODE+CDE = 180  70 = 110. 
November 27th, 2017, 11:38 AM  #22 
Senior Member Joined: Dec 2015 From: holland Posts: 162 Thanks: 37 Math Focus: tetration 
I used the facts that the sum of the angles in a triangle is 180 degrees as is a straight line. A negative angle doesn't make sense but 5 and 55 are the only solutions of the equations in my previous post. 
November 27th, 2017, 11:39 AM  #23 
Senior Member Joined: Dec 2015 From: holland Posts: 162 Thanks: 37 Math Focus: tetration  
November 27th, 2017, 11:48 AM  #24 
Senior Member Joined: Dec 2015 From: holland Posts: 162 Thanks: 37 Math Focus: tetration 
OED = 5 ODE = CDE = 55 CED = 105 Just fill it in.. it is correct. Last edited by manus; November 27th, 2017 at 11:55 AM. 
November 27th, 2017, 12:04 PM  #25 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038  
November 27th, 2017, 12:13 PM  #26 
Senior Member Joined: Feb 2010 Posts: 711 Thanks: 147  
November 27th, 2017, 12:26 PM  #27 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 14,597 Thanks: 1038  
December 1st, 2017, 08:44 PM  #28 
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