Draw a figure based on given instructions:
Let O be the position of the observer and AB be the tower standing on a level ground.
OA = 20 m and ∠OAB = 90° and ∠AOB = 60°
Here, AB = h meters
From the right ∆OAB, we get
tan 60° = AB/OA = √3
h/20 = √3
h = 34.64
Height of the tower is 34.64 m