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						Math: Geometry Problem 1005: 
						Triangle, Circle, Circumcenter, Interior and Exterior 
						Angle Bisector, 90 Degree, Perpendicular. Level: School, College.
              The figure below shows a triangle ABC 
				with circumcenter O. BD and BE are the interior and exterior 
				bisectors of angle B. If Q is the circumcenter of triangle DBE, 
				prove that the measure of angle OBQ is 90 degrees.
 
				 
 
 
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