Sorry, but I disagree. The dropped bullet accelerates from zero velocity without any other significant force other than gravity. The ricochet has a "running start" due to its momentum. If its velocity is 1500-fps, then I believe that 2/90 = .0222222 X 1500 = 33.33 fps vertically is its "running start."
A projectile follows the following path defined by its horizontal (x) and vertical coordinates (y):
x=x
0 + v
0cos(θ)t
y= y
0 + v
0sin(θ)t - (1/2)gt
2See:
http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html#tra5If you apply that to your situation,
x=x
0=0;
(1) v
0cos(2)t=250 ft.
y=y
0=0;
v
0sin(2)t=250 sin(2)=8.7 ft
(2) (1/2)gt
2=16t
2=5 ft
This last equation (2) means t= √(5/16)=0.56 seconds
Substituting into (1) gives v
0=250/(.56x.9994)=447 fps