The airplane rises at an angle of 14° with respect to the ground.
You have to find the distances (diagonal) that it frew if it covered a horizontal distance of 1500 feet.
The distance flew by the place with respect to the horizontal ground and the height the plane is at after traveling 1500 feet form a right triangle. Where x represents the hypothenuse of the triangle. To determine its measure, you have to use the trigonometric relations

Given that θ=14° and we know that the adjacent side to the angle measures 1500 feet, using the cosine we can determine the length of x as:

The distance flew by the airplane is 1545.92ft