In fact, this is writen in "E" -> target data assesment charts:
But this on the image is incomplete information.
This Equation is right only if colision point angle is 90 degrees, thats what i mean by fire at 90 AoB.
If its not 90, complete Equation is
range * sine(AoB)/ sine(angle of track).
Since sine(90) = 1, its
range * sine(AoB)/ 1, which is simply
range * sine(AoB) as i said.