Trigonometrical Ratios Class-9 RS Aggarwal ICSE Maths Goyal Brothers Prakashan Chapter-20. We provide step by step Solutions of Exercise / lesson-20 Trigonometrical Ratios for ICSE Class-9 RS Aggarwal Mathematics .

Our Solutions contain all type Questions with Exe-20 (A), Exe-20 (B), , Exe-20 (C), and  Exe-20 (D), and Notes to develop skill and confidence. Visit official Website for detail information about ICSE Board Class-9 Mathematics.

 Board ICSE Publications Goyal brothers Prakshan Subject Maths Class 9th Chapter-20 Trigonometrical Ratios Writer RS Aggrawal Book Name Foundation Topics Solution of Exe-20 (A), Exe-20 (B), , Exe-20 (C), and  Exe-20 (D), and Notes to develop skill and confidence Academic Session 2021-2022

Trigonometrical Ratios Class-9 RS Aggarwal ICSE Maths Goyal Brothers Prakashan Chapter-20

–: Select Topics :–

Notes on Trigonometrical Ratios

Exe-20 (A),

Exe-20 (B),

Exe-20 (C),

Exe-20 (D),

Notes on Trigonometrical Ratios

The ratio between the lengths of a pair of two sides of a right-angled triangle is called a Trigonometrical Ratio. The three sides of a right-angled triangle give six trigonometrical ratios; namely sine, cosine, tangent, cotangent, secant, and cosecant.

Definition

Trigonometry is the study of relationships between the sides and angles of a triangle

The word “trigonometry” is derived from the Greek words “tri” (meaning three), “gon”(meaning sides) and “metron”(meaning measure)

Right angled triangle ABC

• Side AC is called the hypotenuse of the right angle
• Side AB is called the side adjacent to angle A or base
• Side BC is called the side opposite to angle A or perpendicular
• If we consider angle C, then
• Side BC is called the side adjacent to angle C
• Side AB is called the side opposite to angle C

Important properties

• Each trigonometric ratio is a real number and has no unit
• The values of the trigonometric ratios of an angle do not vary with the lengths of the sides of the triangle, if the angle remains the same
• Since the hypotenuse is the longest side in a right triangle, the value of sin A or cos A is always less than 1 (or, in particular, equal to 1)

Exe-20 (A),Trigonometrical Ratios Class-9 RS Aggarwal ICSE Maths Goyal Brothers Prakashan

Page 242-243

Question 1:

Look at the figure given below :

……………….

Question 2:

In the given ……………….. = 3 units.

Find :

(i) sin A

(ii)cos A

……………..

…………………….

…………………….

…………………….

Question 21:

In the given ………………………  lengths of AB and BC.

Question 22:

If cos θ ………….. in θ in terms of x.

Trigonometrical Ratios Exe-20 (B) , Class-9 RS Aggarwal ICSE Maths Goyal Brothers Prakashan

Page 249-250

Question 1 : Without using trigonometric tables, find the value of :
(i) sin ………………………
Question 2: ……………………..
………………………
………………………
Question 14: Without using tables, verify that :
(i) ………
…………..
Question 15: If 0 ≤ x ≥ 90, state the numerical value of x for which sin x = cos x.

RS Aggarwal Exe-20 (C), Trigonometrical Ratios Class-9  ICSE Maths Goyal Brothers Prakashan

Page 254-255

Question 1:

(i) ​$$\frac{sin 27^{\circ}}{cos 63^{\circ}}$$

(ii)…………..

……………

…………….

…………….

Question 14:

Prove that : sin (50 + θ) – ……………… = 0

Question 15:

Prove that : tan (45 – A) …………… = 1

Prove that :

(i)………………

…………………..

Trigonometrical Ratios Class-9 RS Aggarwal ICSE Maths Goyal Brothers Prakashan  Exe-20 (D),

Page 257

Question 1:

A balloon is connected to a metrological station by a cable …………………. in the string.

………………………

……………………….

……………………….

Question 6:

In a rectangle ABCD, AB = 12 cm and ………………… side BC and diagonal Ac.

–: End of Trigonometrical Ratios Class-9 RS Aggarwal ICSE Class-9th Maths Solutions   :–

Thanks