A <a href="https://en.wikipedia.org/wiki/Cyclic_polygon" class="extiw" title="en:Cyclic polygon">cyclic polygon</a> (in this case a pentagon) can be partitioned into <a href="https://en.wikipedia.org/wiki/Isosceles_triangle" class="extiw" title="en:Isosceles triangle">isosceles triangles</a> by the radii of its circumscribing circle through its vertices.
<a href="//commons.wikimedia.org/wiki/User:David_Eppstein" class="mw-redirect" title="User:David Eppstein">David Eppstein</a>
<span class="int-own-work" lang="en">Own work</span>