.2طﻮل اﻟﻘﻄﻌﮫ اﻟﻮاﺻﻠﮫ ﺑﯿﻦ راس اﻟﻘﺎﺋﻤﮫ وﻣﻨﺘﺼﻒ اﻟﻮﺗﺮ ﻓﻲ اﻟﻤﺜﻠﺚ اﻟﻘﺎﺋﻢ اﻟﺰاوﯾﮫ ﯾﺴﺎوي ﻧﺼﻒ اﻟﻮﺗﺮ . ½= BDاﻟﻮﺗﺮ .3طﻮل اﻟﻀﻠﻊ اﻟﻤﻘﺎﺑﻞ ﻟﻠﺰاوﯾﮫ 30ﻓﻲ اﻟﻤﺜﻠﺚ اﻟﻘﺎﺋﻢ اﻟﺜﻼﺛﯿﻨﻲ ﺳﺘﯿﻨﻲ ﯾﺴﺎوي ﻧﺼﻒ اﻟﻮﺗﺮ . 4 = ABﺳﻢ