Morley's trisector theorem

Trisect the angles of any triangle and the adjacent intersections will form an equilateral triangle. Drag the corners and see for yourself!

Written using the D3 visualisation library. Inspired by A Better Nature.

Requires a SVG-capable browser e.g. Mozilla Firefox, WebKit (Google Chrome, Safari &c.) or Internet Explorer 9.

Links and Proofs

• A. Bogomolny, Morley's Miracle from Interactive Mathematics Miscellany and Puzzles. Includes a long list of different proofs, in particular John Conway's proof is rather elegant.
• Morley's Trisection Theorem: a detailed proof at MathWorld.
• Morley's Theorem at MathWorld.
• Morley's trisector theorem at Wikipedia.

© Jason Davies 2012.