Answer: It’s angle of elevation is 48.6 degrees (approximately)
Step-by-step explanation: Please refer to the picture attached for details.
If the plane travels for 400 meters from the runway and is currently at a height of 300 meters from the ground, then the plane is at point A. The distance travelled so far is line CA, while the height from the ground is line AB. The angle of elevation formed is at angle C where the plane started it’s journey.
To calculate angle we would use the trigonometric ratio since we have derived a right angled triangle with C as the reference angle and line AB as the opposite (facing the reference angle) and also line AC as the hypotenuse (longest side/side facing the 90 degree angle).
SinC = opposite/hypotenuse
SinC = 300/400
SinC = 3/4
SinC = 0.7500
From your calculator or a table of values,
C = 48.5903
Approximately angle C = 48.6 degrees