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						|  Problem 190. 
						Tangent circles, Tangent chord, Perpendicular, Diameter, Distance |  
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              In the figure below, AB is the 
				diameter of circle of center O and radius r. OB is the diameter 
				of circle of center O'. The chord AD is tangent to circle O' at 
				E. If DF is perpendicular to AB and BF = x, prove that 				 .
				View or post a solution. 
 
				 
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						Poster and Typography of Problem 
						190
		 
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