Page 18 - Engineering

‫ﺍﳌﺴﺘﻘﻴﻤﺎﺕ ﻭﺍﻟﺰﻭﺍﻳﺎ ‪٥‬‬

‫ﻧﻘﻄﺔ واﻗﻌﺔ ﺑﻴﻦ ﻧﻘﻄﺘﻴﻦ )‪ :(a point between two points‬ﻧﻘﻮل إن اﻟﻨﻘﻄﺔ ‪C‬‬
‫ﻋﻠﻰ اﳌﺴﺘﻘﻴﻢ ‪ AB‬ﺗﻘﻊ ﺑﲔ اﻟﻨﻘﻄﺘﲔ ‪ A‬و ‪ B‬إذا وﻓﻘﻂ إذا ﻛﺎن‬
‫‪ . AC + CB = AB‬ﻧﺴﺘﺨﺪم ﻋﺎدة اﻟﺮﻣﺰ ‪ ACB‬ﻟﻴﻌﲏ أن اﻟﻨﻘﻄﺔ ‪ C‬ﺗﻘﻊ‬

‫ﺑﲔ ‪ A‬و ‪.B‬‬

‫‪AC‬‬ ‫‪B‬‬

‫اﻟﺸﻌﺎع )‪ :(ray‬اﻟﺸﻌﺎع )أو ﻧﺼﻒ اﳌﺴﺘﻘﻴﻢ( اﻟﺬي ﻳﺒﺪأ ﺑﺎﻟﻨﻘﻄﺔ ‪ A‬ﺑﺎﲡﺎﻩ اﻟﻨﻘﻄﺔ ‪B‬‬
‫ﻳﺮﻣﺰ ﻟﻪ ﺑﺎﻟﺮﻣﺰ ‪ AB‬وﻫﻮ اﲢﺎد ﳎﻤﻮﻋﺔ ﻧﻘﺎط ‪ AB‬وﳎﻤﻮﻋﺔ ﲨﻴﻊ اﻟﻨﻘﺎط ‪ C‬ﲝﻴﺚ‬

‫ﺗﻘﻊ ‪ B‬ﺑﲔ ‪ A‬و ‪.C‬‬

‫‪AB‬‬ ‫‪C‬‬

‫اﻟﺸﻌﺎع ‪AB‬‬

‫وإذا ﻛﺎﻧﺖ اﻟﻨﻘﻄﺔ ‪ C‬واﻗﻌﺔ ﺑﲔ اﻟﻨﻘﻄﺘﲔ ‪ A‬و ‪ B‬ﻋﻠﻰ اﳌﺴﺘﻘﻴﻢ ‪ AB‬ﻓﺈﻧﻨﺎ ﻧﻘﻮل‬
‫إن اﻟﺸﻌﺎﻋﲔ ‪ CA‬و ‪ CB‬ﻣﺘﻌﺎﻛﺴﺎن‪.‬‬

‫‪AC‬‬ ‫‪B‬‬

‫‪ CA‬ﻣﻌﺎﻛﺲ ﻟﻠﺸﻌﺎع ‪CB‬‬

‫اﻟﻘﻄﻊ اﻟﻤﺴﺘﻘﻴﻤﺔ اﻟﻤﺘﻄﺎﺑﻘﺔ )‪ :(congruent segments‬ﻧﻘﻮل إن اﻟﻘﻄﻌﺘﲔ‬
‫اﳌﺴﺘﻘﻴﻤﺘﲔ ‪ AB‬و ‪ CD‬ﻣﺘﻄﺎﺑﻘﺘﺎن وﻧﻜﺘﺐ ‪ AB ≡ CD‬إذا ﻛﺎن‬

‫‪) AB = CD‬أي ‪.(AB = CD‬‬