Answer: 40.96 meters.
Explanation:
Hi, since the situation forms a right triangle (see attachment) we have to apply the trigonometric functions.
sin α = opposite side / hypotenuse
Where α is the angle of elevation of the string to the ground, the hypotenuse is the longest side of the triangle (in this case is the length of the string), and the opposite side (x) is the length of the kite above the ground
Replacing with the values given:
sin 55 = x/ 50
Solving for x
sin55 (50) =x
x= 40.96 m
Feel free to ask for more if needed or if you did not understand something.