# What is inversion and how does it act on figure inscribed in a circle?

Trying to wrap my head around inversions. I understand it takes things from inside to outside, such that the distance from some point inside circle + the distance to new point is r^2 where r is radius of circle of inversion. How would this look with a figure not just one line? for example a triangle inscribed in a circle? I know angles are supposed to be preserved

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Let $O$ be the centre of the circle, $P$ our point "inside" and $Q$ the point it s mapped to. Then $(OP)(OQ)=r^2$. (Your expression in terms of sums is not quite right.) –  André Nicolas Nov 16 '12 at 5:37
You might find this video enlightening: ima.umn.edu/~arnold/moebius –  Blue Nov 16 '12 at 6:18
i.stack.imgur.com/gQbt4.png –  Rahul Nov 16 '12 at 6:23
Let $O$ be the centre of the circle, $P$ our point "inside" and $Q$ the point it s mapped to. Then $(OP)(OQ)=r^2$. (Your expression in terms of sums is not quite right.)