Q40 of 68 Page 9

A tall tree stands vertically on a bank of a river. At the point on the other bank directly opposite the tree, the angle of elevation of the top of the tree is 60°. At a point 20 m behind this point on the same bank, the angle of elevation of the top of the tree is 30°. Find the height of the tree and the width of the river.


From the ∆ADC,




From the ∆ABC,




= 17.32


put value of h in equation(i)


So,


Therefore, the height of tree is 17.32 m and width of the river is 10 m.


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