Home › Forums › Math questions › Geometry questions

What is the length of the tangent segment from a circle to a common external point.

Posted April 6th, 2011 by DaveAtkNH
in

What is the length of the segment of two tangent lines to a circle of known radius which meet at a known known angle at a common external point?

In the following link, what is the length PN (or PM) given the angle NPM and radius of the circle?

equal tangents

Answer

$$PM=R\cot\frac{\angle NMP}{2}$$

‹ Circles Projection of a circle to a plane in 3D ›

Back to top