August 14th, 2017, 10:34 AM  #1 
Newbie Joined: Aug 2016 From: Pakistan Posts: 9 Thanks: 0  Please Help Me about this problem
Using property of Circles please solve this problem Thanks in Advance

August 14th, 2017, 01:00 PM  #2 
Global Moderator Joined: May 2007 Posts: 6,451 Thanks: 567 
Your note is very hard to read. I suggest you type it in directly.

August 14th, 2017, 03:01 PM  #3 
Math Team Joined: Jul 2011 From: Texas Posts: 2,722 Thanks: 1376 
Your solution is correct.

August 14th, 2017, 03:24 PM  #4 
Global Moderator Joined: Dec 2006 Posts: 18,698 Thanks: 1527 
The answer is essentially correct, but it should be stated that angle A is calculated based on the fact that the angles of a triangle sum to 180°. The theorem about angles subtended is stated inaccurately. The reflex angle subtended by the major arc AC at O is 360°  60°  60° = 240°. Hence (by the inscribed angle theorem) the angle subtended by that arc at B (the angle you want to find) is 240°/2, which is 120°. 