Question

一道简单的几何题在线段AB上有两点C,D,AC:CB=3:7,AD:DB=2:3,AB长20cm,求CD长.

Answer 1

AC:CB=3:7---AC:AB=3:10,AB=20cm----AC=6cm

AD:DB=2:3---AB:DB=5:3,AB=20cm----BD=12cm

所以CD=AB-AC-BD=20-6-12=2cm