求助啊 gwd math.23 Q34 立体几何

echoetmoi

Q34:

In the figure, each side of square ABCD has length 1, the length of line segment CE is 1, and the length of line segment BE is equal to the length of line segment DE.  What is the area of the triangular region BCE?

A.      1/3

B.      (Ö2)/4

C.      1/2

D.      (Ö2)/2

E.       3/4

Answer: B

je04tta

用BDE减去BTopway的面积再除以2就是了，BDE的高就是CE加正方形对角线的一半