A kite is attached to a 100 m long string. Find the greatest height reached by the kite when its string makes an angle of 60° with the level ground.

AC is the string and BC is the height of kite.

In Δ ABC,

$\text{sin 60°} = \dfrac{Perpendicular}{Hypotenuse}\\[1em] ⇒ \dfrac{\sqrt3}{2} = \dfrac{BC}{AC}\\[1em] ⇒ \dfrac{\sqrt3}{2} = \dfrac{BC}{100}\\[1em] ⇒ BC = \dfrac{\sqrt3 \times 100}{2}\\[1em] ⇒ BC = 50\sqrt3 = 86.60$

Hence, the greatest height reached by the kite = 86.60 m.