I keep getting this answer wrong. Can you help me?

A projectile fired into the first quadrant from the origin of a coordinate system will pass through the 2x point (x,y) at time t according to the relationship cot 0 = - where 0 is the angle of elevation 2y + gt2 of the launcher and g is the acceleration due to gravity (32.2 feet/second-). An artilleryman is firing at an enemy bunker located 2575 feet up the side of a hill that is 6250 feet away. He fires a round, and exactly 2.89 seconds later he scores a direct hit. (a) What angle of elevation did he use? 0 = 25.6 (Do not round until the final answer. Then round to one decimal place as needed.)