A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is_______________? August 16, 2021January 25, 2019 by admin A projectile is fired at an angle 9 to the vertical. Its horizontal range will be maximum when 9 is_______________? A. 0° B. 30°C. 45° D. 60° E. 90°.