How can you find the velocity of a bullet fired from a nerf gun the second it leaves the gun, if all you have is the angle it was shot at, and how far it traveled?

Question

How can you find the velocity of a bullet fired from a nerf gun the second it leaves the gun, if all you have is the angle it was shot at, and how far it traveled? 
(All in degrees)
0 degrees=2.54m
10=6.24m
30=6.54m
45=6.58m
60=1.6m
80=.94m

Steve · Answer

The range of a projectile fired with speed v at an angle θ is R = v^2/g sin2θ So, plug in your numbers and see what drops out for v.