Horizontal component = V cos(30°) = V (√3/2) = 73.2 m/s
Vertical component = V sin(30°) = V (0.5) = 100 m/s
In 6 seconds, the object travels horizontally (173.2 m/s x 6 sec) = 1,039 m
After 6 seconds, the object's height above the ground is
H = V₀t + 1/2 a t²
H = (100 m/s)(6 s) + (1/2) (-9.8 m/s²) (6 s)²
H = (600 m) - (4.9 m/s²) (36 s²)
H = (600 m) - (176.4 m)
Height = 423.6 m