# how to calculate an arc center

how to find the center of an arc given start and end points

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@user3310: An arc of a circle is defined by three non-colinear points. –  Américo Tavares Nov 9 '10 at 14:58
Another way of phrasing Américo's statement: you can't determine a radius from just start and end points. –  Ｊ. Ｍ. Nov 9 '10 at 15:34