اﻟﺰاوﯾﮫ اﻟﺨﺎرﺟﯿﮫ ﻟﻠﻤﺜﻠﺚ = ﻣﺠﻤﻮع ﻗﯿﺎس اﻟﺰاوﯾﺘﯿﻦ اﻟﺪاﺧﻠﯿﺘﯿﻦ اﻟﺒﻌﯿﺪﺗﯿﻦ . 160 = 80+70=X * ﻣﺠﻤﻮع ﻗﯿﺎس اﻟﺰواﯾﺎ اﻟﺨﺎرﺟﯿﮫ ﻟﻠﻤﺜﻠﺚ = 360ﺑﻨﻔﺲ اﻻﺗﺠﺎه * ﻣﺠﻤﻮع ﻗﯿﺎس اﻟﺰواﯾﺎ اﻟﺪاﺧﻠﯿﮫ ﻟﻠﻤﺜﻠﺚ = 180 اﻋﺪاد اﻟﻄﺎﻟﺒﮫ :ﺳﻨﺪس اﺣﻤﺪ ﺧﻀﯿﺮات .