Last updated at July 18, 2019 by Teachoo

Transcript

Ex 9.1, 1 A circus artist is climbing a 20 m long rope, which is tightly stretched and tied from the top of a vertical pole to the ground. Find the height of the pole, if the angle made by the rope with the ground level is 30° Let, the height of pole be AB. Assuming that rope is tied at point C. It is given that, Length of rope = 20 m Hence, AC = 20m Also, angle made by rope with the ground level = 30° Hence, ∠ACB=30° We need to find height of pole i.e. AB Since the pole is vertical, ∠ ABC = 90° In right triangle ABC sin C = (𝑆𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 𝑎𝑛𝑔𝑙𝑒" " 𝐶" " )/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 sin 30°= 𝐴𝐵/𝐴𝐶 (1 )/2 = 𝐴𝐵/20 1/2×20 = AB 10 = AB AB = 10 ∴ Height of pole = AB = 10 metre.

Questions easy to difficult

Angle of Elevation and Angle of Depression

Angle of Depression from point A to point B is same as Angle of Elevation from point B to point A

How to find Height when angle of elevation is given?

How to find Distance when angle of depression is given?

Example 1

EX 9.1, 4

EX 9.1, 1 You are here

EX 9.1, 3

EX 9.1, 2

EX 9.1, 5

Ex 9.1, 7

Example 2

Example 3

Example 4

EX 9.1, 8

Example 5

Ex 9.1, 6

EX 9.1, 9

Ex 9.1, 10

Ex 9.1, 11

Example 6 Important

Ex 9.1, 12

Ex 9.1, 13 Important

Ex 9.1, 16

Example 7

Ex 9.1, 14 Important

Ex 9.1, 15 Important

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.