CBSE Class 10 Maths Notes Chapter 9 Some Applications of Trigonometry Pdf free download is part of Class 10 Maths Notes for Quick Revision. Here we have given NCERT Class 10 Maths Notes Chapter 9 Some Applications of Trigonometry. According to new CBSE Exam Pattern,Â MCQ Questions for Class 10 Maths Carries 20 Marks. https://www.cbselabs.com/some-applications-of-trigonometry-class-10-notes/

## CBSE Class 10 Maths Notes Chapter 9 Some Applications of Trigonometry

**Some Applications Of Trigonometry Class 10 Notes Chapter 9**

**Line of Sight**

When an observer looks from a point E (eye) at an object O then the straight line EO between the eye E and the object O is called the line of sight.

**Horizontal**

When an observer looks from a point E (eye) to another point Q which is horizontal to E, then the straight line, EQ between E and Q is called the horizontal line.

**Applications Of Trigonometry Class 10 Notes Chapter 9**

**Angle of Elevation**

When the eye is below the object, then the observer has to look up from the point E to the object O. The measure of this rotation (angle Î¸) from the horizontal line is called the angle of elevation.

**Angle of Depression**

When the eye is above the object, then the observer has to look down from the point E to the object. The horizontal line is now parallel to the ground. The measure of this rotation (angle Î¸) from the horizontal line is called the angle of depression.

How to convert the above figure into the right triangle.

**Case I:** Angle of Elevation is known

Draw OX perpendicular to EQ.

Now âˆ OXE = 90Â°

Î”OXE is a rt. Î”, where

OE = hypotenuse

OX = opposite side (Perpendicular)

EX = adjacent side (Base)

**Case II:** Angle of Depression is known

(i) Draw OQ’parallel to EQ

(ii) Draw perpendicular EX on OQ’.

(iii) Now âˆ QEO = âˆ EOX = Interior alternate angles

Î”EXO is an rt. Î”. where

EO = hypotenuse

OX = adjacent side (base)

EX = opposite side (Perpendicular)

- Choose a trigonometric ratio in such a way that it considers the known side and the side that you wish to calculate.
- The eye is always considered at ground level unless the problem specifically gives the height of the observer.

The object is always considered as a point.

**S**ome **P**eople **H**ave

Sin Î¸ = \(\frac { Perpendicular }{ Hypotenuse }\)

**C**urly **B**lack **H**air

Cos Î¸ = \(\frac { Base }{ Hypotenuse }\)

**T**urning **P**ermanent **B**lack.

Tan Î¸ = \(\frac { Perpendicular }{ Base }\)

**Class 10 Maths Chapter 9 Introduction **

### Class 10 Maths Notes

- Chapter 1 Real Numbers Class 10 Notes
- Chapter 2 PolynomialsÂ Class 10 Notes
- Chapter 3 Pair of Linear equations in Two Variables Class 10 Notes
- Chapter 4 Quadratic Equations Class 10 Notes
- Chapter 5 Arithmetic Progressions Class 10 Notes
- Chapter 6 Triangles Class 10 Notes
- Chapter 7 Coordinate Geometry Class 10 Notes
- Chapter 8 Introduction to Trigonometry Class 10 Notes
- Chapter 9 Some Applications ofÂ Trigonometry Class 10 Notes
- Chapter 10 Circles Class 10 Notes
- Chapter 11 Constructions Class 10 Notes
- Chapter 12 Areas related to Circles Class 10 Notes
- Chapter 13 Surface Areas and Volumes Class 10 Notes
- Chapter 14 Statistics Class 10 Notes
- Chapter 15 Probability Class 10 Notes