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The easiest way I know how to explain this is with a picture so here it is: http://pbrd.co/19RxqqV

For simplicity the origin is 0,0 and the angles are easy to work with but they could potentially be anything. The only things I really consistently know for this type of problem is the rotation of the circle, the origin and the radius and then of course the new degree/rotation of the circle.

This question, I think is similar but not really the exact same thing: Finding the coordinates on the edge of a circle

Thanks! I hope my question is clear enough.

Community
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Eric
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  • For a general answer, see [this](http://math.stackexchange.com/questions/2429/rotate-a-point-in-circle-about-an-angle). You can find it by simple equations as described in that post. – Shamim Hafiz - MSFT Jun 19 '13 at 17:33

1 Answers1

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The coordinates of a point with angle a with respect to x-axis on a circle of radius r are:

x = r*cos(a*Pi/180), y = r*sin(a*Pi/180)

In your case a=45+135

Emanuele Paolini
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  • This seems to be what I need but I'm still running into a few problems. Sometimes my origin is not at 0,0 what I found though is if I add my original Origin to the equation it seems to set it in the relative area and my point rotates around the circle mostly appropriately. Like so: x = originX + r*cos(a*Pi/180), y = originY + r*sin(a*Pi/180) I'll have to try a little bit more though because whenever I set the rotation of the circle to 0 then my coordinates for the blue plot end up starting at 180 degrees every time. – Eric Jun 19 '13 at 20:51