If the red had a base of 5 it would be 2/5, and a straight edge along a print out will confirm that the diagonals are perfectly straight on both triangles.
If you look at the red fifth column from the left on both diagrams the drop is exactly the same.
The straight line can not have 2 different slopes (rise over run). There are 2 different slopes: 2/5 and 3/8. Rise (Right side) over Run (Bottom side) of the red and green triangles.