Given:
The altitude of the kite, h=120 ft.
The angle made by the kite string with the ground, θ=55° .
Let x be the length of the string.
Now, using trigonometric property in the above triangle,
[tex]\begin{gathered} \sin \theta=\frac{opposite\text{ side}}{hypotenuse} \\ \sin \theta=\frac{h}{x} \end{gathered}[/tex]Now, substitute the values and solve the equation for x.
[tex]\begin{gathered} \sin 55^{\circ}=\frac{120\text{ ft}}{x} \\ x=\frac{120\text{ ft}}{\sin55^{\circ}} \\ =146.49\text{ ft} \\ \approx146\text{ ft} \end{gathered}[/tex]Therefore, length of the kite string is 146 ft.