Let A be the position of the kite in the sky. Let C be the position on the ground from where a string is attached to the kite. Since we have assumed that there is no slack in the string, we take AC to be a straight line making 60° angle with the ground. Draw a perpendicular from A on the ground which meets at point B. The kite is flying at a height of 75 m above the ground. So, AB = 75 m. Join B and C. We thus get a triangle ABC with right angle at B. We are to find the length of the string that is AC. We will use the trigonometric ratio sine which uses the perpendicular AB and the hypotenuse AC to find AC. Now, ∠ ACB = 60°

From ∆ABC,

or,

The length of the string is 86.60 m.