单项选择题
设A(x1,y1),B(x2,y2),C(x3,y3)为平面上不共线的三点,则三角形ABC的面积为( )。
A. [img=152,53]teacher-zt-1109/3646546t-57.jpg[/img]
B. [img=138,63]teacher-zt-1109/3646546t-58.jpg[/img]
C. [img=114,34]teacher-zt-1109/3646546t-59.jpg[/img]
D. [img=139,33]teacher-zt-1109/3646546t-60.jpg[/img]