<p>Let&nbsp;\(A\), \(B\), \(C\) and \(D\) be vertices of the cyclic quadrilateral \(ABCD\). Show that&nbsp;\(AC \times BD = AB \times CD + BC \times AD\).</p>
<div class="content-block"><figure class="question-figure alignright" style="text-align: right;"><img src="https://vocwkpgapvksartxhhor.supabase.co/storage/v1/object/public/question-images/pasted/1775801319211-iiuu83q5mw.png" style="max-width: min(180px, 100%); height: auto; display: block;" alt="Cyclic quadrilateral ABCD" class="alignright custom-width" /></figure></div>

Let \(A\), \(B\), \(C\) and \(D\) be vertices of the cyclic quadrilateral \(ABCD\). Show that \(AC \times BD = AB \times CD + BC \times AD\).

Proof of Ptolemy’s Theorem

Proof of Ptolemy’s Theorem