Let the height of this trapezoid be x cm.

Green triangle area =ah/2=4x/2=2x

The area of the red triangle =ah/2= 10x/2=5x.

Trapezoidal area =(a+b)h/2=(4+ 10)x/2=7x.

2x/5x=2/5

7x/5x=7/5

A: The area of the green triangle is 2/5 of that of the red triangle, and the area of the trapezoid is 7/5 of that of the red triangle.

It's over, I hope to adopt it, the process is more important than the result!