Given that initial speed of ball, u=81.4 m/s making an angle, x = 18.9 degree
The total time taken will be,
[tex]t=\frac{2u\sin \text{ x}}{g}[/tex]Here, g is acceleration due to gravity whose value is 9.8 m/s.
Substituting the values, we get
[tex]t=\frac{2\times81.4\times\sin (18.9^{\circ}\text{)}}{9.8}[/tex]Hence the total time is 5.38 seconds.