They were comparable in this respect because both aspect ratios of the top triangle are one square more. The top triangle is equal to the base triangles if you remove one square away from the height and width.
Otherwise, we can say that it forms all different. The dilation factor which translates that bottom left point of shape I to form II is 2. But this does not map the other shape I vertices onto form II. There's, therefore, no dilation in form I of maps on form II.
