Assignment #7






Michelle Nichols



Given two circles and a point on one of the circles, construct a circle tangent to the two circles with one point of tangency being the designated point.




When the center point of our tangent circle is traced, what do we get?  Let’s see…


We get an ellipse, with Foci at center of both our original circles.  What if the circles are disjoint, meaning the smaller circle lies outside the larger circle?  Observe this construction…



The locus when the circles are disjoint is a hyperbola, rather than an ellipse.  The Foci, once again, lie at the radius of the small circle and large circle. Take a look at the sketch of the locus of the hyperbola and ellipse, once again, without the circles. 








For a GSP script tool of the tangent circle, click here.



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