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NCERT Solutions for Class 10 Maths Exercise 8.1 Class 10 Maths book solutions are available in PDF format for free download. These ncert book chapter wise questions and answers are very helpful for CBSE board exam. CBSE recommends NCERT books and most of the questions in CBSE exam are asked from NCERT text books. Class 10 Maths chapter wise NCERT solution for Maths Book for all the chapters can be downloaded from our website and myCBSEguide mobile app for free.

**NCERT solutions for Maths ****Introduction to Trigonometry ****Download as PDF**

## NCERT Solutions for Class 10 Maths Introduction to Trigonometry

**1. In ****ABC, right angled at B, AB = 24 cm, BC = 7 cm. Determine:**

**(i) **

**(ii) **

**Ans. **Let us draw a right angled triangle ABC, right angled at B.

Using Pythagoras theorem,

= = 576 + 49 = 625

AC = 25 cm

**(i) **,

**(ii) **,

**2. In adjoining figure, find ****:**

**Ans. **Using Pythagoras theorem,

=169 – 144 = 25

QR = 5 cm

= = = 0

NCERT Solutions for Class 10 Maths Exercise 8.1

**3. If **** calculate **** and **

**Ans. **Given: A triangle ABC in which B =

Let BC = and AC =

Then, Using Pythagoras theorem,

AB = =

= =

NCERT Solutions for Class 10 Maths Exercise 8.1

**4. Given **** find **** and **

**Ans. **Given: A triangle ABC in which B =

Let AB = and BC =

Then using Pythagoras theorem,

AC =

=

=

= =

NCERT Solutions for Class 10 Maths Exercise 8.1

**5. Given **** calculate all other trigonometric ratios.**

**Ans. **Consider a triangle ABC in which A = and B =

Let AB = and BC =

Then, using Pythagoras theorem,

BC =

=

=

= =

NCERT Solutions for Class 10 Maths Exercise 8.1

**6. If ****And ****B are acute angles such that **** then show that ****A = ****B.**

**Ans. **In right triangle ABC,

and

But [Given]

AC = BC

A = B

[Angles opposite to equal sides are equal]

NCERT Solutions for Class 10 Maths Exercise 8.1

**7. If **** evaluate:**

**(i) **

**(ii) **

**Ans. **Consider a triangle ABC in which A = and B =

Let AB = and BC =

Then, using Pythagoras theorem,

AC =

=

=

= =

**(i) ** =

= = =

**(ii) ** = =

NCERT Solutions for Class 10 Maths Exercise 8.1

**8. If **** check whether **** or not.**

**Ans. **Consider a triangle ABC in which B = .

And

Let AB = and BC =

Then, using Pythagoras theorem,

AC =

=

=

= =

And

Now, L.H.S. =

= =

R.H.S. =

= =

L.H.S. = R.H.S.

=

NCERT Solutions for Class 10 Maths Exercise 8.1

**9. In ****ABC right angles at B, if **** find value of:**

**(i) **

**(ii) **

**Ans. **Consider a triangle ABC in which B = .

Let BC = and AB =

Then, using Pythagoras theorem,

AC =

=

= = =

For C, Base = BC, Perpendicular = AB and Hypotenuse = AC

**(i) ** =

= = 1

**(ii) ** =

=

NCERT Solutions for Class 10 Maths Exercise 8.1

**10. In ****PQR, right angled at Q, PR + QR = 25 cm and PQ = 5 cm. Determine the values of ****nd **

**Ans. **In PQR, right angled at Q.

PR + QR = 25 cm and PQ = 5 cm

Let QR = cm and PR = cm

Using Pythagoras theorem,

RQ = 12 cm and RP = 25 – 12 = 13 cm

And

NCERT Solutions for Class 10 Maths Exercise 8.1

**11. State whether the following are true or false. Justify your answer.**

**(i) The value of **** is always less than 1.**

**(ii) **** for some value of angle A.**

**(iii) **** is the abbreviation used for the cosecant of angle A.**

**(iv) **** is the product of **** and A.**

**(v) **** for some angle **

**Ans. (i) False** because sides of a right triangle may have any length, so may have any value.

**(ii)** **True** as is always greater than 1.

**(iii) False** as is the abbreviation of cosine A.

**(iv) False** as is not the product of ‘cot’ and A. ‘cot’ is separated from A has no meaning.

**(v) False** as cannot be > 1.

## NCERT Solutions for Class 10 Maths Exercise 8.1

NCERT Solutions Class 10 Maths PDF (Download) Free from myCBSEguide app and myCBSEguide website. Ncert solution class 10 Maths includes text book solutions from Mathematics Book. NCERT Solutions for CBSE Class 10 Maths have total 15 chapters. 10 Maths NCERT Solutions in PDF for free Download on our website. Ncert Maths class 10 solutions PDF and Maths ncert class 10 PDF solutions with latest modifications and as per the latest CBSE syllabus are only available in myCBSEguide.

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