Battle of the Iron Triangle Battle of the Iron Triangle The Battle of the Iron Triangle took place from 16 May to 20 November 1974, when the People's Army of Vietnam (PAVN) 9th Division captured Rach Bap and An Dien The Army of the Republic of Vietnam (ARVN) regained the lost towns in a series of costly counterattacks. The Iron Triangle was an important strategic location, bounded on the north by the jungle and overgrown rubber plantations of the Long Nguyen Secret Zone, on the west by the Saigon River and on the east by the smaller but unfordable obstacle of the Thi Thinh River.
Conway triangle notation Conway triangle notation In geometry, the Conway triangle notation, named after John Horton Conway, allows trigonometric functions of a triangle to be managed algebraically. Given a reference triangle whose sides are "a", "b" and "c" and whose corresponding internal angles are "A", "B", and "C" then the Conway triangle notation is simply represented as follows: where "S" = 2 × area of reference triangle and in particular Furthermore the convention uses a shorthand notation for formula_14 and formula_15 Hence: Some important identities: where "R" is the circumradius and "abc" = 2"SR" and where "r" is the incenter, formula_22 and formula_23