9. In the figure, AB // DC. If the areas of DABE and DCDE are 4 and 9 respectively, find the area of DBCE.
A. 4
B. 5
C. 6
D. 6.5
E. 9
圖:
http://www.sendspace.com/file/bhtk7x
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數學maths一問
2008-06-07 6:59 pm
回答 (1)
2008-06-07 7:28 pm
✔ 最佳答案
Triangle ABE is similar to triangle DEC (AAA). Therefore, Area of triangle ABE : Area of triangle DEC = AE^2 : EC^2 (similar figure)
That is 4/9 = AE^2/EC^2, therefore, AE/EC = 2/3.
Therefore, area of triangle ABE : area of triangle BEC = 2 : 3
That is 4/area of triangle BEC = 2/3, therefore, area of triangle BEC= 3 x 4/2 = 6.
收錄日期: 2021-04-25 22:35:49
原文連結 [永久失效]:
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