Abaseball player hits a ball. the table represents a quadratic function that shows how the height of the ball changes over time.

what does the y-coordinate of the vertex represent?

X - axis represents the time ( in seconds )
y - axis represents the height ( in feet );
After x = 0.50 s we have the maximum height ( y = 9 ft ).
Therefore the vertex of the quadratic function is ( 0.50, 9 )

- The maximum height ( in feet ) that the ball reaches.