Chapter 13 - Height and Distance

Example 2. A person standing on the bank of a river observes that the angle of elevation of the top of a tree standing on the opposite bank is 600. When he moves 40m away from the bank, he finds the angle of elevation to be 300. Find the height of the tree and the width of the river.

Solution:- Let height of the tree be y and width of the river be x. CD = 40m

In

tan 300 = AB/BD

In

tan 600 =AB/BC

Putting value of y from (ii) to (i)

Height of the tree =

Width of the river = 20m.

 

Maths by Mr. M. P. Keshari
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Subjects Maths (Part-1) by Mr. M. P. Keshari
Chapter 9 Circle
Chapter 10 Tangents to a circle
Chapter 11 Geometrical Construction
Chapter 12 Troigonometry
Chapter 13 Height and Distance
Chapter 14 Mensuration
Chapter 15 Statistics
Chapter 16 Probability
Chapter 17 Co-ordinate Geometry