A TV tower stands vertically on a bank of a canal. From a point on the other bank directly opposite the tower, the angle of elevation of the top of the tower is 60°. From another point 20 m away from this point on the line joining this point to the foot of the tower, the angle of elevation of the top of the tower is 30° (see Fig. 9.12). Find the height of the tower and the width of the canal


According to this figure:

CD = 20 m,


ACB = 60°,


ADB = 30°,


AB = ? and BD = ?


In Δ ABC,






In Δ ABD,





𝐹rom (i) and (ii),





Using the value of BC in (i) we get;


AB = 10√3 m which is the height of the tower


Width of canal = 10 m


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