August 25th, 2018, 03:47 AM  #1 
Newbie Joined: Aug 2018 From: uttar pradesh india Posts: 1 Thanks: 0  find radius of the circle 
August 25th, 2018, 06:14 AM  #2 
Global Moderator Joined: Dec 2006 Posts: 20,632 Thanks: 2080 
You'll need some further information or assumptions. For example, can you assume that AB is a tangent to the circle at B? Even if you can, you'll need some further information. 
August 25th, 2018, 07:26 AM  #3 
Member Joined: Jan 2018 From: Belgrade Posts: 55 Thanks: 2 
Yes, it seems that result isn't unique with given inputs. (See pictures.) In spite of that, it can be shown that $\displaystyle \triangle ABD \sim \triangle ABC$, $\displaystyle AC=18 cm$, $\displaystyle DC=10 cm$ and $\displaystyle \frac{BC}{BD}=\frac{3}{2}$. To find $\displaystyle r$ (using the law of sines, for example), it is necessary to provide more data. Last edited by lua; August 25th, 2018 at 07:35 AM. 

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