# Exterior Tangents to Three Circles

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Two nonintersecting circles have one pair of common interior tangents and one pair of common exterior tangents. The interior tangents intersect at a point on the segment between the the centers; the exterior tangents intersect outside that segment when the circles have different radii (otherwise they are parallel to the line joining the centers).

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Contributed by: Izidor Hafner (September 2012)

Open content licensed under CC BY-NC-SA

## Snapshots

## Details

D. Wells, *The Penguin Book of Curious and Interesting Puzzles*, New York: Penguin, 1993 p. 150.

## Permanent Citation

"Exterior Tangents to Three Circles"

http://demonstrations.wolfram.com/ExteriorTangentsToThreeCircles/

Wolfram Demonstrations Project

Published: September 28 2012