Page 77 - Engineering
P. 77
ﺍﳍﻨﺪﺳﺔ )ﺍﳉﺰء ﺍﻷﻭﻝ( ٦٤
A
B CD
][ABC ] = [ABD] − [ACD
= 1 (BD)ha − 1 (CD)ha
2 2
= 1 (BD − CD)ha
2
= 1 (BC )ha
2
= 1 aha
2
وﻫﺬا ﻳﻨﻬﻲ اﻟﱪﻫﺎن.
ﺑﺮﻫﺎن اﻟﻤﺒﺮﻫﻨﺔ )] (٥ﻣﺒﺮﻫﻨﺔ ﻓﻴﺜﺎﻏﻮرس[ :ﻟﻨﻔﺮض أن △ABCﻗﺎﺋﻢ اﻟﺰاوﻳﺔ ﰲ .C
أﻧﺸﺊ ﻣﺮﺑﻌﺎً ﻃﻮل ﺿﻠﻌﻪ a + bﻛﻤﺎ ﻫﻮ ﻣﺒﲔ ﰲ اﻟﺸﻜﻞ أدﻧﺎﻩ
bE a
ac cb
D
A
c ca
b
C a Bb F