NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.1

# NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.1

## NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.1

NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.1 are the part of NCERT Solutions for Class 11 Maths. Here you can find the NCERT Solutions for Class 11 Maths Chapter 3 Trigonometric Functions Ex 3.1.

#### Ex 3.1 Class 11 Maths Question 1.

Find the radian measures corresponding to the following degree measures:
(i) 25°
(ii) -47°30′
(iii) 240°
(iv) 520°

Solution.
We have, 180° = Ï€ Radians

#### Ex 3.1 Class 11 Maths Question 2.

Find the degree measures corresponding to the following radian measures (Use Ï€ = 22/7).
(i) 11/16
(ii) -4
(iii) 5Ï€/3
(iv) 7Ï€/6

Solution.
We have Ï€ Radians = 180°

#### Ex 3.1 Class 11 Maths Question 3.

A wheel makes 360 revolutions in one minute. Through how many radians does it turn in one second?

Solution.
The number of revolutions made by the wheel in one minute = 360
We know that, 1 revolution = 2Ï€ Radians
In 1 minute, the wheel can make = 720Ï€ Radians
In 60 seconds, the wheel can make = 720Ï€ Radians
In 1 second, the wheel can make 720Ï€/60 Radians = 12Ï€ Radians

#### Ex 3.1 Class 11 Maths Question 4.

Find the degree measure of the angle subtended at the centre of a circle of radius 100 cm by an arc of length 22 cm (Use Ï€ = 22/7).

Solution.
Let O be the centre and AB be the arc length of the circle.

#### Ex 3.1 Class 11 Maths Question 5.

In a circle of diameter 40 cm, the length of a chord is 20 cm. Find the length of minor arc of the chord.

Solution.
Let AB be the minor arc of the chord.
AB = 20 cm, OA = OB = 20 cm

#### Ex 3.1 Class 11 Maths Question 6.

If in two circles, arcs of the same length subtend angles 60° and 75° at the centre, find the ratio of their radii.

Solution.
Let r1, r2 and Î¸1, Î¸2 be the radii and angles subtended at the centre of two circles respectively.

#### Ex 3.1 Class 11 Maths Question 7.

Find the angle in radian through which a pendulum swings if its length is 75 cm and the tip describes an arc of length
(i) 10 cm
(ii) 15 cm
(iii) 21 cm

Solution.

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