The graph models the height of a miniature parachute, in feet, x seconds after it is thrown straight up in the air from the fifth floor of a building. What does the x-coordinate of the vertex represent? The parachute reached its maximum height after 2.5 s. The parachute’s maximum height was 2.5 ft above the fifth floor. The parachute was in the air for 2.5 s. It took 2.5 s for the parachute to fall to the ground after reaching its maximum height.