國中數學 幾何圖形?
回答 (1)
2017-04-16 8:43 pm
Sol
△ACD=2△ABD
CD=2BD，AC=2AB
Set AB=x，BD＝y，AD=z
x^2+(3y^2)=(2x)^2
x^2+9y^2=4x^2
3x^2=9y^2
x^2=3y^2
x^2+y^2=z^2
3y^2+y^2=z^2
z=2y=CD
△ACD=2△ABD
CD=2BD，AC=2AB
Set AB=x，BD＝y，AD=z
x^2+(3y^2)=(2x)^2
x^2+9y^2=4x^2
3x^2=9y^2
x^2=3y^2
x^2+y^2=z^2
3y^2+y^2=z^2
z=2y=CD
收錄日期: 2021-04-30 22:09:39
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20170416121435AAHBssd