How long it takes to reach maximum height in seconds

The dotted path is the path of the ball. it reaches it's maximum height at the top where vertical, y-velocity = 0
The initial y-velocity = 19sin(70°)
initial y-velocity = 17.85 m/s

Use one of the kinematic equations with velocity and time. No displacement because we don't want to worry about figuring that out.

v = u - gt
0 = 17.85 - 9.8t
-17.85 = -9.8t
17.85/9.8 = t
1.82 sec = t