I want to simulate an arrow's trajectory. All I need to know is at what angle the projectile needs to be launched at for it to reach a destination with a set initial velocity (speed).

Someone pointed out how this post Trajectory -math, c# was similar to mine, and to answer that yes it is almost the exact same, just that I am not interested in adding the wind factor. But the answers don't seem to give or hint at the formula of how to calculate the angle, and only the angle, needed for the projectile to reach the destination. If this is incorrect please point this out.