Find ce centre of an arc tangent to 2 cercles....

Hello I draw a circle at 0,0 rP I draw another circle at 200,0 R0 I want to draw an arc perfectly tangent to both circle (in such a way that, when finished, the whole looks a little bit like an ellipse quarter) arc radius is 400 How can I find EXACTLY the arc center position? Thank you for help
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Hint: The center on the unknown arc will be 350 from circle 1 and 300 from circle 2.
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<> I draw a circle at 0,0 rP <> I draw another circle at 200,0 R0 <> I want to draw an arc perfectly tangent to both circle (in such a way that, <> when finished, the whole looks a little bit like an ellipse quarter) <> arc radius is 400 <> How can I find EXACTLY the arc center position
<Hint: <The center on the unknown arc will be 350 from circle 1 and 300 from <circle 2.
You are right That's crazy simple but I didn't find it! Thank you for your help!
hpspt

Why don't you just draw an cricle using the TTR option? Start circle and enter TTR. Pick the two circles and enter the radius. Then you can use the ID and cen commands to find the center of the circle, which hapopen to be 181.25,-299.4125,0.
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There are actually many circles which are tangent to 2 others, simulating an ellipse; the reason being you can choose tangent points in a more or less large section of the circles depending on how far away you are from the circles. You will need to determine this variable.
If both circles on each side are equal, your "ellipse" center will be on a perpendicular to the middle point of the circles. The missing point lies somewhere along this perpendicular.
Hope this helps.
Dr Fléau
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