Historical clue formulations

• Unit of angular measurement — 2026-04-08
• Angular unit of measurement — 2026-02-12
• Trigonometry unit — 2024-06-07
• Measure equal to about 57° — 2020-06-19
• Angular measurement — 2019-03-10
• Angular measurement — 2004-09-10
• Angle measurement — 1995-11-12