No products in the cart.

AB is a straight road leading …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

AB is a straight road leading to C,  the foot of a tower, A being at a distance of 120m from C and B being 75m nearer. If the angle of elevation of the tower at B is the double of the angle of elevation of the tower at A,  find the height of the tower. 

  • 2 answers

Naveen Sharma 7 years, 3 months ago

Just consider the image for Reference. 

Gievn : AB is straigt Road and C is the foot of tower. Let DC is tower of height h, and AC is 120cm and BC is 45 cm as it is 75cm nearer than A.

Solution : In Triangle BCD 

tan 60° = h45

=> h = 45 tan 2x  => h = 45 2tanx 1-tan2x   .............. (1) tan 2x = 2tan x1-tan2x

In Triangle, ACD

tan x = h120

=> h = 120 tan x       .................... (2)

From (1) and (2)

120 tanx = 45×2 tanx 1-tan2x

=> 1-tan2x = 34

=> tan2x = 14

=> tan x = 12

Put value of tan x in (2)

we get h = 60 

so height of tower is 60cm

Shweta Gulati 7 years, 3 months ago

Are you sure this is the question? Please check it once.

http://mycbseguide.com/examin8/

Related Questions

Prove √2-5as irrational
  • 0 answers
Ch 3 ex 3.3
  • 1 answers
3.11stques
  • 0 answers
7+7+√7
  • 1 answers
a+b ka hool square
  • 0 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App