Raymond J. answered 12/22/20
Patient with Ability to Explain in Many Ways
Since we're assuming the rocket traveled straight up, we have a 90° angle.
We have x = 5, y = 8, so distance between the rocket and you is d2 = 52 + 82 = 89, or d = √(89)
Using law of sines, we get
√(89)/sin(90) = 8/sin(θ) or sin(θ) = 8/(√(89)) ⇒ θ ≈ 58°