I'm pretty sure that the lip of all ramps are the same. It's actually pretty easy to figure out the size with some trig.
Take the 25 degree ramp.
First, we need to find the hypotenuse of the ramp, because the lip messes it up.
The 45 degree has a triangle length of 1 brick.
Here is the formula:
Cosθ=a/h
Let a=the length of the ramp (here it is 1)
Let h=the hypotenuse
Let θ=the angle of the ramp.
.:
Cos(45)=(1)/h
1/cos(45)=h
H~1.414 brick lengths long
Now, we find the height of the ramp triangle, unfortunately in brick lengths, not height. We need to figure out the conversion factor for that.
Here is the formula:
Sinθ=o/h
Let o=the height of the ramp triangle
Let h=the hypotenuse of the ramp triangle
Let θ=the angle of the ramp
.:
Sin(45) = o/(1.414)
(1.414)sin(45) = o
o = .99984 brick lengths.
Once we figure out the brick length to brick height in plates conversion factor, we cause this formula.
X-(Y*Z) = Q
Where X is the ramp brick's height in plates
Where Y is the height of the ramp Brock's triangle in brick lengths (here it is .99984 Bl)
Where Z is the conversion factor in terms of (Brick Heights in plates per Brick Length; Bh/Bl)
Where Q is the height of the ledge.
Now someone figure out the length-to-height conversion factor.