A projectile is launched at an angle of 9 degrees measured from the vertical. At which angle 9 will the horizontal distance covered by the projectile be the greatest?

Explanation

When a projectile is fired at an angle from the vertical, the horizontal range is maximized when the angle from the vertical is 45 degrees. This corresponds to the classic result that the maximum range occurs at a 45-degree angle from the horizontal, so when measured from the vertical, it is also 45 degrees.