Editing Concyclic points (section)

== Perpendicular bisectors ==
In general the centre ''O'' of a circle on which points ''P'' and ''Q'' lie must be such that ''OP'' and ''OQ'' are equal distances. Therefore ''O'' must lie on the [[perpendicular bisector]] of the line segment ''PQ''.<ref>{{citation
 | last = Libeskind | first = Shlomo
 | isbn = 9780763743666
 | page = 21
 | publisher = Jones & Bartlett Learning
 | title = Euclidean and Transformational Geometry: A Deductive Inquiry
 | url = https://books.google.com/books?id=6YUUeO-RjU0C&pg=PA21
 | year = 2008}}/</ref> For ''n'' distinct points there are [[triangular number|''n''(''n''&nbsp;−&nbsp;1)/2]] bisectors, and the concyclic condition is that they all meet in a single point, the centre ''O''.