题目内容：

已知m是线段的中点,am=10厘米,若在直线AB上有一点C,AB比BC=5比2,求MC的长度

优质解答

AM=10
MB=10
AB=2AM=20
AB:BC=5:2
BC = 2AB/5 = 2*20/5 = 8
当C点在AB延长线上时：MC = MB+BC = 10+8 = 18
当C点在AB之间时：MC = MB-BC = 10-8 = 2