December 4th, 2016, 09:09 AM  #1 
Newbie Joined: Dec 2016 From: Romania Posts: 2 Thanks: 0 
I have a geometry problem to solve: in the triangle ABC, the measure of BAC=120, ABC=20. In the inside of the triangle is a point O so that the measure of OAB=100 and OBA=10. Find the measure of OCA. Thank you for the help. Last edited by skipjack; December 5th, 2016 at 05:11 AM. 
December 5th, 2016, 06:40 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,373 Thanks: 2010 
The answer is 10°, but I don't yet have an elegant proof of this.

December 5th, 2016, 10:32 AM  #3 
Newbie Joined: Dec 2016 From: Romania Posts: 2 Thanks: 0 
that's true, we have to proof this without using trigonometry


Tags 
angle, find, measure 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
Find the measure of angle x  mared  Geometry  6  March 23rd, 2015 05:42 PM 
How can I find the angle X  Yasir  Algebra  10  February 10th, 2013 08:57 PM 
measure smaller angle  kingkos  Algebra  18  December 21st, 2012 02:18 AM 
how to find angle  mariasp  Complex Analysis  7  October 22nd, 2012 05:40 AM 
Find the angle  naserellid  Algebra  6  August 15th, 2010 03:54 PM 