Find the coordinates of a point on a circle without knowing the center point.by b1gd0g Tags: circle, coordinates, knowing, point 

#1
Sep911, 03:20 PM

P: 2

Given 2 points on a circle, call them A and B. I know the cartesian coordinates of A. I also know the radius of the circle, the slope of the tangent line at A, and the length and direction of the arc between A and B. I don't know the coordiates of the center of the circle.
How do I find the coordinates of point B? 



#2
Sep911, 03:26 PM

Sci Advisor
P: 5,941

The radius at A is perpendicular to the tangent line. The center is along the radius at a known distance. There are only two possible points. Use the information about B (direction of arc??) to choose the location of the center.




#3
Sep911, 03:31 PM

P: 2

Thanks mathman. I just needed a little insight, and you have provided that quickly and succinctly.



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