Answer:
2378 m
Explanation:
You want the ground distance from the takeoff point to an airplane that has flown 2500 m in the air at a takeoff angle of 18°.
Cosine
The cosine relation tells you ...
Cos = Adjacent/Hypotenuse
Adjacent = Hypotenuse · Cos
Application
Here, the hypotenuse of the right triangle model is 2500 m, the angle is 18°, and we want to find the side of the triangle adjacent to the angle:
AD = AP·cos(18°) = 2500·0.9510565 ≈ 2377.64 ≈ 2378 . . . . meters
The ground distance is about 2378 m.