This is a fantastic question developed by Catriona Agg - https://www.instagram.com/p/CZ9m_KRMBn_/?utm_source=ig_web_copy_link 0:00 Intro 0:20 Tangent 1:15 Pythagoras 2:25 Thales 2:41 Similar Triangles 3:25 Ratios 3:55 Solve for the diameter