NCERT Class 10 Maths — Chapter 8

Exercise 8.1: Trigonometric Ratios

Find sin, cos, and tan of angles in right triangles. The foundation of everything in trigonometry.

sin cos tantrigonometric ratiosright triangle ratios
11
NCERT Questions
10
Practice MCQs
3
Key Concepts
Free
With Answers

Extra Practice Questions

These questions cover the same concepts as Exercise 8.1. Try solving them to build confidence before or after the textbook exercise.

1

In a right-angled triangle ABC, right-angled at B, if AB = 8 cm and BC = 6 cm, what is the value of tan A?

A.3/4
B.4/3
C.3/5
D.4/5
2

Simplify: (1 - sin²A) / (1 - cos²A)

A.tan²A
B.cot²A
C.sec²A
D.cosec²A
3

In a right-angled triangle ABC, right-angled at B, P is a point on BC such that BP:PC = 1:2. If ∠BAC = θ and ∠BAP = φ, what is the value of (tan θ) / (tan φ)?

A.1/3
B.1/2
C.2
D.3
4

If x = a sec θ cos φ, y = b sec θ sin φ, and z = c tan θ, then what is the value of (x²/a² + y²/b² - z²/c²)?

A.0
B.1
C.2
D.3
5

Which of the following statements about trigonometric ratios for an acute angle A is ALWAYS true?

A.sin A > 1
B.sec A < 1
C.tan A can be greater than 1
D.cos A can be 5/3
6

If sin θ = 12/13, what is the value of cosec θ?

A.13/12
B.5/12
C.12/5
D.1/13
7

Evaluate the expression: 2 × sin 30° + tan 45°.

A.1
B.2
C.3/2
D.5/2
8

Evaluate: (sin 60° × cos 30° + sin 30° × cos 60°)

A.0
B.1/2
C.1
D.√3/2
9

If sin A + sin² A = 1, then what is the value of cos² A + cos⁴ A?

A.0
B.1
C.2
D.sin A
10

The value of (sin 25° cos 65° + cos 25° sin 65°) is:

A.A) 0
B.B) 1
C.C) sin 40°
D.D) cos 40°

Stuck on a question?

Paste any question from Exercise 8.1 into our AI Maths Solver and get a step-by-step solution instantly. It works for all NCERT questions.

Try AI Solver — Free

Common Mistakes to Avoid

  • Confusing opposite and adjacent sides (depends on which angle you're looking at)
  • Not using Pythagoras to find the missing side first
  • Mixing up sin and cos

Other Exercises in Chapter 8

Frequently Asked Questions

How many questions are in Exercise 8.1?

Exercise 8.1 has 11 questions on computing trigonometric ratios from right triangles.

Want to practise on paper? Download a free worksheet for this topic.

Download Worksheet PDF