Page 20 - Engineering

‫ﺍﳌﺴﺘﻘﻴﻤﺎﺕ ﻭﺍﻟﺰﻭﺍﻳﺎ ‪٧‬‬

‫اﻟﺤﻞ‪. EC = 3 1 − (−4) = 7 1 :‬‬

‫‪22‬‬

‫ﻣﺜﺎل )‪ :(٣‬إذا ﻛﺎن ‪ AB = 5‬و ‪ BC = 2‬و ‪ AC = 7‬ﻓﺄي ﻣﻦ اﻟﻨﻘﺎط‬
‫‪ C ،B ،A‬ﺗﻘﻊ ﺑﲔ اﻟﻨﻘﻄﺘﲔ اﻷﺧﺮﻳﲔ ؟‬
‫اﻟﺤﻞ‪ B :‬ﺗﻘﻊ ﺑﲔ ‪ A‬و ‪ C‬ﻷن‬

‫‪AC = 7 = 5 + 2 = AB + BC‬‬

‫ﻣﺜﺎل )‪ :(٤‬اﻟﻌﻼﻗﺔ ﺑﲔ ﻧﻘﺎط اﻟﻘﻄﻌﺔ اﳌﺴﺘﻘﻴﻤﺔ‬

‫‪A CB‬‬
‫‪O x 21‬‬

‫ﻫﻲ ‪ . AC = 2 CB‬ﻣﺎ ﻗﻴﻤﺔ ‪ x‬؟‬
‫اﻟﺤﻞ‪ :‬ﲟﺎ أن ‪ C‬ﺗﻘﻊ ﺑﲔ ‪ A‬و ‪ B‬وأن ‪ AC = 2 CB‬ﻓﺈن‬
‫‪. AB = AC + CB = 2 CB + CB = 3 CB‬‬
‫إذن‪ . CB = 21 = 7 ،‬و‪‬ﺬا ﻳﻜﻮن ‪ AC = 14‬وﻣﻦ ﰒ ‪.x = 14‬‬

‫‪3‬‬

‫اﻟﺰواﻳﺎ وﻗﻴﺎﺳﻬﺎ ]‪[Angles and their Measure‬‬

‫ﺗﻌﺮﻳﻒ‪ :‬ﺗُﻌﺮف اﻟﺰاوﻳﺔ ﻋﻠﻰ أ‪‬ﺎ اﲢﺎد ﺷﻌﺎﻋﲔ ﻳﺸﱰﻛﺎن ﰲ ﻧﻘﻄﺔ اﻟﺒﺪاﻳﺔ‪ .‬ﺗﺴﻤﻰ ﻧﻘﻄﺔ‬
‫اﻟﺒﺪاﻳﺔ رأس اﻟﺰاوﻳﺔ وﻳﺴﻤﻰ اﻟﺸﻌﺎﻋﺎن ﺿﻠﻌﻲ اﻟﺰاوﻳﺔ‪ .‬ﻓﻤﺜﻼً‪،‬‬

‫‪C‬‬ ‫‪B‬‬
‫‪x‬‬

‫‪A‬‬