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Jonas
Posts:
23
Registered:
4/9/06


Alternate Formula for Radius of a Circle
Posted:
Jul 6, 2006 2:51 AM


I am doing some review of basic math. I ran accross an answer in a Schwaum's book that I can't make sense of and I wasn't able to derive the formula either. Here is the problem.
Find the standard equation of the circle with center at (1,3) and tangent to the line 5x12y8=0.
To find the radius, the book uses the following formula 5(1)12(3)6/13=3.
I solved the problem in a different way and got the right answer but I couldn't figure out how the above equation was created and why it works.
Any insight you could give would be appreciated.



