ANSWER
[tex]8.72s[/tex]EXPLANATION
To find the time of flight, apply the formula for a projectile's time of flight:
[tex]T=\frac{2u\sin \theta}{g}[/tex]where u = initial velocity
θ = angle of launch
g = acceleration due to gravity
Therefore, the time of flight of the cannonball is:
[tex]\begin{gathered} T=\frac{2\cdot85.5\cdot\sin 30}{9.8} \\ T=8.72s \end{gathered}[/tex]