Tangent Circles to Two Parallel Lines and Passing through a Point

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This Demonstration is based on an example from a Wolfram Education Group seminar: Given two parallel lines and a point between them, draw circles of radius centered at and through and tangent to the lines. Then the circle centered at with radius passes through and .


Here we allow the two blue circles to be constructed when the point is not between the two lines.


Contributed by: Abraham Gadalla (July 2011)
Open content licensed under CC BY-NC-SA



The distance from a point in the - plane to the line with equation , where is the slope of the line and is the intercept, can be proven to be .

See the Wolfram Education Group seminar, Calculus: Fundamentals.

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