A <a href="//commons.wikimedia.org/wiki/Circle" class="mw-redirect" title="Circle">circle</a> showing the chord, segment, radius, diameter and tangent.
<a href="//commons.wikimedia.org/wiki/User:Jleedev" title="User:Jleedev">Jleedev</a>
<span class="int-own-work" lang="en">Own work</span> in Inkscape 0.42