February 23rd, 2017, 12:47 PM  #1 
Newbie Joined: Jan 2017 From: London Posts: 10 Thanks: 0  Finding the radius
I'm struggling to find the radius of the circle in the image (the only other given length is the length between B and the right angle below, which is 5). Is it even possible to get the radius without knowing any other dimensions? Or is there a way to find it? I've tried to use Pythagoras but without knowing the length of the side of the triangle going towards O, it was hard to find it. https://docs.google.com/document/d/1...a_JLHQy2Q/edit 
February 23rd, 2017, 01:19 PM  #2 
Global Moderator Joined: May 2007 Posts: 6,512 Thanks: 585 
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February 24th, 2017, 06:28 AM  #3 
Newbie Joined: Jan 2017 From: London Posts: 10 Thanks: 0 
Sorry mathman... Here is the image: If you knew the length of a as 5.6, and no other information was given, would it be possible to find the radius? If not, what other lengths would you have to know? Are there more than one way of getting the radius? 
February 24th, 2017, 01:37 PM  #4 
Global Moderator Joined: May 2007 Posts: 6,512 Thanks: 585 
The length of an arbitrary chord is insufficient to determine the radius. Include the length of the line from O to P as additional information will work. Alternative use the angle $\displaystyle \theta $

February 25th, 2017, 09:31 AM  #5 
Member Joined: Jan 2016 From: Athens, OH Posts: 88 Thanks: 47 
In your original post, you said another length was given as 5. I couldn't figure our what length is 5. I thought maybe it was PX, but this is impossible with a=5.6. Here's some more discussion: 
February 25th, 2017, 12:59 PM  #6 
Newbie Joined: Jan 2017 From: London Posts: 10 Thanks: 0 
The picture that I originally wanted to post was different from the one you saw after. So there was no other information at all other than the chord length. I don't need help anymore since I've already solved it 

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