perplexus.info :: Geometry : Concyclic Points of Tangency

Concyclic Points of Tangency (Posted on 2013-07-02)

Consider four circles each of which is
externally tangent to two of the others.

Prove that the four points of tangency
are concyclic.

See The Solution Submitted by Bractals

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re: Solution

Comment 2 of 2 |

(In reply to Solution by Jer)

I get

AWZ = 90-A/2

BWX = 90-B/2 (not BWC)

ZWX = (A+B)/2

XYZ = (C+D)/2

ZWX+XYZ = (A+B+C+D)/2 = 360/2 = 180

Posted by Bractals on 2013-07-04 14:29:19

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