I am trying to write an Excel template which will chart two circles and their external tangent lines - similar to a belt and two pulley system.(adsbygoogle = window.adsbygoogle || []).push({});

I have the formulas to calculate and chart the circles. I am looking for a formula to calculate the tangent points between the circles, given the following criteria:

Circle 1 will always have a center at 0,0

Circle 2 will always be larger than circle 1

Center points of both circles will always be on the X axis

Diameters and center distances are known, and will change with the system design

Is there such a formula published?

Thank you

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# Circle to Circle Tangent Equation

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