Iron Triangle (Vietnam) Iron Triangle (Vietnam) The Iron Triangle (Vietnamese:"Tam Giác Sắt") was a area in the Bình Dương Province of Vietnam, so named due to it being a stronghold of Viet Minh activity during the war. The region was under control of the Viet Minh throughout the French war in Vietnam and continued to be so throughout the phase of American involvement in the Vietnam War, despite concerted efforts on the part of US and South Vietnamese forces to destabilize the region as a power base for their enemy, the communist North Vietnamese–sponsored and–directed South Vietnamese insurgent movement, the National Liberation Front
Extouch triangle the sides of the reference triangle at the three vertices of the extouch triangle. The area of the extouch triangle, formula_7, is given by: where formula_9, formula_10, formula_11 are the area, radius of the incircle and semiperimeter of the original triangle, and formula_12, formula_13, formula_14 are the side lengths of the original triangle. This is the same area as that of the intouch triangle. Extouch triangle In geometry, the extouch triangle of a triangle is formed by joining the points at which the three excircles touch the triangle. The vertices of the extouch triangle are given in trilinear coordinates by: