Line of Sight
Horizontal
Angle of Elevation
Angle of Depression
The topics discussed in this chapter are as follows:
- Horizontal Level and Line of Sight
- Angle of elevation
- Angle of depression
- Calculating Heights and Distances
Students can view and download the chapter from the link given below.
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NCERT Solutions for Chapter 9: Some Applications of Trigonometry
Also Check
Chapter 1: Real Numbers
Chapter 2: Polynomials
Chapter 3: Pair of Linear Equations in Two Variables
Chapter 4: Quadratic Equations
Chapter 5: Arithmetic Progression
Chapter 6: Triangles
Chapter 7: Coordinate Geometry
Chapter 8: Introduction to Trigonometry
Chapter 10: Circle
Chapter 11: Constructions
Chapter 12: Areas Related to Circles
Chapter 13: Surface Areas and Volume
Chapter 14: Statistics
Chapter 15: Probability
Check out Frequently Asked Questions (FAQs) for Chapter 9: Some Applications of Trigonometry
The angle of elevation of the top of a building from a point on the ground, which is 30 m away from the foot of the building, is 30°. The height of the building is
Say x is the height of the building.
a is a point 30 m away from the foot of the building.
Here, height is the perpendicular and distance between point a and foot of building is the base.
The angle of elevation formed is 30°.
Hence, tan 30° = perpendicular/base = x/30
1/√3 = x/30
x = 30/√3
From a point on the ground, which is 15 m away from the foot of the tower, the angle of elevation of the top of the tower is found to be 60°. The height of the tower (in m) standing straight is
We know:
tan (angle of elevation) = height of tower/its distance from the point
tan 60° = h/15
√3 = h/15
h = 15√3
If the height of the building and distance from the building foot’s to a point is increased by 20%, then the angle of elevation on the top of the building ___________.
We know, for an angle of elevation θ,
tan θ = Height of building/Distance from the point
If we increase both the value of the angle of elevation remains unchanged.