An angle of elevation of 58 degrees with the ground means that the angle started at the x-axis and terminates on the first quadrant region through a counter clockwise direction. Imagining a triangle, the string of the kite becomes the hypotenuse, the angle 58 degrees is the angle between the hypotenuse and the ground, and the height of the kite is the side opposite to the angle.
Therefore, we can calculate for the height of the kite using the sin function:
sin θ = opposite side / hypotenuse
sin 58 = opposite side / 50 m
opposite side = 50 m * sin 58
opposite side = 42.4 m
Therefore the kite is about 42.4 m above the ground.