±è§ÎABCD¤¤¡A½uAD¥­¦æ½uBC¡A½uAD=7¡A½uCD=11, ¨¤Dµ¥©ó¤G­¿ªº¨¤B¡A¨D±è§Îªº¤¤½uªø

12.5

°µ¤@­Ó¥­¦æ¥|Ãä§Î ADCH ¡A¦Ó¥B H ¦b BC ½u¤W
¥i¥Hª¾¹D CH = AD = 7

¥ý°²³] ¨¤B = x «×¡A
«h ¨¤AHC = ¨¤ADC = 2¨¤B = 2x
¤S ¨¤BAH = ¨¤AHC - ¨¤ABH
= 2x - x
= x
= ¨¤B
¡÷BH = AH = DC = 11
ºî¦X¤W­z¥iª¾¤¤½u= ( AD + BC )/2
= ( AD + BH +HC )/2
= 12.5
~THE EHD~

AD/2=3.5 , CD/2=5.5
¡î2tanB=tanD=11/7, 11/7/2=11/14=5.5/7
¡ï7+3.5=10.5¡Î
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°µADC¨¤¥­¤À½u¥æBC©óE
¦]¨¤D=2¨¤B
©Ò¥H¨¤ADE=¨¤B
ABED¬°¥­¦æ¥|Ãä§Î
AD=BE
¤S¨¤DEC=¨¤B
¨¤EDC=¨¤B
©Ò¥H¤T¨¤§ÎDEC¬°µ¥¸y¤T¨¤§Î
DC=CE=11
¤¤¿¤±`¬°(7+11+7)=12.5

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°µ¤@­Ó¥­¦æ¥|Ãä§Î ADCH ¡A¦Ó¥B H ¦b BC ½u¤W
¥i¥Hª¾¹D CH = AD = 7

¥ý°²³] ¨¤B = x «×¡A
«h ¨¤AHC = ¨¤ADC = 2¨¤B = 2x
¤S ¨¤BAH = ¨¤AHC - ¨¤ABH
= 2x - x
= x
= ¨¤B
¡÷BH = AH = DC = 11
ºî¦X¤W­z¥iª¾¤¤½u= ( AD + BC )/2
= ( AD + BH +HC )/2
= 12.5
~THE EHD~
¶§©ú°ê¤¤¸êÀu¯Z 201 µL²á§B§B

12.5

_________________
...ahaha...