So imagine you have a triangle (created by the kite and the ground), and one of the bottom angles is 30 degrees. The side opposite to that angle is 18 m. To find the hypotenuse (the kite string), you must use trig functions. You can use sine, since it is the same as opposite over hypotenuse. Set up the problem as sin (30) = 18/x (x equals the kite string). Solve for x, and you should get 36 m. That means the kite string is 36 m long.
