# Straightedge Only Construction of Tangents to Circle

Currently, there exists a question regarding straightedge only constructions; however, my specific question pertains something that is not found in that thread, and I do not think it will be answered any time soon for that matter.

Foreplay aside, my question centers around the following simple fact:

Given a circle $\Gamma$ and a point $P$ outside of $\Gamma$, it is possible to construct the two tangent lines from $P$ to the circle by straightedge alone, using the straightedge only construction of the polar line.

My question is - where can I find a proof (or perhaps, could I be supplied with one) that this construction works?

Thanks in advance for any assistance. This is not homework, just mere curiosity.

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## 1 Answer

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Thanks for the link, I will give that a read! I was wondering if there was a textual reference (i.e. print source) of the proof as well - the typesetting and presentation on that site is not the cleanest to say the least. –  Tim Zhou Sep 17 '12 at 19:52