let the pole is BC which makes an angle of 60° with the vertical, then ∠CBA=30° And CD=BD
AB = x meter and AD is common in both triangles Then both the triangles are congruence then It means, ∠ADB=∠ADC Now as we now AD cut the CB then ∠ADB+∠ADC=180° 2∠ADB=180° ∠ADB=90°=∠ADC Now Triangle ADB is right angle triangle Then ABcos30°=BD