Editing Diameter (section)

== Constructions ==
With [[straightedge and compass]], a diameter of a given circle can be constructed as the [[perpendicular bisector]] of an arbitrary chord. Drawing two diameters in this way can be used to locate the center of a circle, as their crossing point.<ref>{{cite book|title=General Drafting|series=Technical manual, TM 5-581A, United States Department of the Army|publisher=U.S. Government Printing Office|year=1972|page=6{{hyphen}}32|contribution=6-66 Finding the center of a circle|contribution-url=https://books.google.com/books?id=1iGqD3y_CggC&pg=SA6-PA32}}</ref> To construct a diameter parallel to a given line, choose the chord to be perpendicular to the line.

The circle having a given line segment as its diameter can be constructed by straightedge and compass, by finding the [[midpoint]] of the segment and then drawing the circle centered at the midpoint through one of the ends of the line segment.