组合嘛.
C9 3
3在9上面
=9*8*7/3*2*1=自己算.
平面上有9个点,3点不共线,在这9个点间任意连接线段,最多能构成多少个三角形?
平面上有9个点,3点不共线,在这9个点间任意连接线段,最多能构成多少个三角形?
数学人气：845 ℃时间：2019-08-21 09:19:23
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