How do you find the center of a circle

Try to post your problem here, there is a chance, someone clever will help you.


How do you find the center of a circle

Postby Cecil Titus » Tue Mar 15, 2005 1:49 am

Cecil Titus

Postby Guest » Sat Mar 19, 2005 1:21 am

It depends on what you have to work with. Two ways:

1) Mathematically: If you have (x,y) coordinates for three points on the circle, you fit the equation:
(x-xc)^2 + (y-yc)^2 = r^2 for the center coordinates (xc, yc) and the radius r. (A fair bit of math)

A graphical form: From the "center" point, construct lines to the other two points. Construct perpendicular bisectors of these lines. They cross in the center.

2) Graphically: From a point outside the circle, construct two tangents (ideally at the point they form about a 90 degree angle). At the points of tangency, construct perpendiculars. They cross in the center of the circle, to the accuracy of your graphical construction.

Return to Other math problems

Who is online

Users browsing this forum: No registered users and 2 guests

Our Privacy Policy       Cooking Measures Converter       Metric conversions