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
Tangential triangle A reference triangle and its tangential triangle are in perspective, and the axis of perspectivity is the Lemoine axis of the reference triangle. That is, the lines connecting the vertices of the tangential triangle and the corresponding vertices of the reference triangle are concurrent. The center of perspectivity, where these three lines meet, is the symmedian point of the triangle. The tangent lines containing the sides of the tangential triangle are called the exsymmedians of the reference triangle. Any two of these are concurrent with the third symmedian of the reference triangle. The reference triangle's circumcircle, its nine-point circle, its