Answer:
7.66m/s
Step-by-step explanation:
Horizontal component of initial speed is

= 10.2 × 0.7660
= 7.66 m/s
horizontal component of the final speed at pinnacle of its trajectory is

= 7.66 m/s
the vertical component of the speed at pinnacle of its trajectory is

the speed of the ball at pinnacle of the trajectory

=

= 7.66m/s