Historical clue formulations

• Trig ratio — 2024-12-13
• Ratio of two sides in a right-angled triangle, in brief — 2022-07-09
• Trig ratio — 2021-04-21
• Trig ratio — 2013-11-10
• Trig function — 2012-04-19
• Trig ratio — 2010-08-21
• Trig function — 1999-12-05
• Trig function — 1994-12-20