November 27th, 2017, 12:34 PM  #21 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,590 Thanks: 953 
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, 12:38 PM  #22 
Senior Member Joined: Dec 2015 From: holland Posts: 163 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, 12:39 PM  #23 
Senior Member Joined: Dec 2015 From: holland Posts: 163 Thanks: 37 Math Focus: tetration  
November 27th, 2017, 12:48 PM  #24 
Senior Member Joined: Dec 2015 From: holland Posts: 163 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 12:55 PM. 
November 27th, 2017, 01:04 PM  #25 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,590 Thanks: 953  
November 27th, 2017, 01:13 PM  #26 
Senior Member Joined: Feb 2010 Posts: 697 Thanks: 135  
November 27th, 2017, 01:26 PM  #27 
Math Team Joined: Oct 2011 From: Ottawa Ontario, Canada Posts: 13,590 Thanks: 953  
December 1st, 2017, 09:44 PM  #28 
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