Answer:
57°
Explanation:
The ladder will be the hypotenuse while the 4.2 meters will be a leg.
We want the angle between the ground & the ladder. Therefore, 4.2 is on the opposite side of the angle.
sin(theta) = opposite/hypotenuse
sin(theta) = 4.2/5
theta = arcsin(4.2/5)
theta = 57°