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Chapter 22 of 28
Flashcards

Trigonometrical Ratios

ICSE · Class 9 · Mathematics

Flashcards for Trigonometrical Ratios — ICSE Class 9 Mathematics. Quick Q&A cards covering key concepts, definitions, and formulas.

44 questions24 flashcards4 concepts
24 Flashcards
Card 1Introduction

What does the word 'Trigonometry' mean?

Answer

Trigonometry means 'measurement of triangles'. In this chapter, we deal specifically with the relations between sides and angles of right-angled triangles.

Card 2Triangle Components

In a right-angled triangle with angle A as the reference angle, identify the perpendicular, base, and hypotenuse.

Answer

For angle A: Perpendicular = side opposite to angle A, Base = side adjacent to angle A, Hypotenuse = side opposite to the right angle (longest side).

Card 3Trigonometric Ratios

Define sine (sin) of an angle in a right triangle.

Answer

Sine of an angle = Perpendicular/Hypotenuse. For angle A, sin A = opposite side/hypotenuse. It is a ratio and has no units.

Card 4Trigonometric Ratios

Define cosine (cos) of an angle in a right triangle.

Answer

Cosine of an angle = Base/Hypotenuse. For angle A, cos A = adjacent side/hypotenuse. It is a ratio and has no units.

Card 5Trigonometric Ratios

Define tangent (tan) of an angle in a right triangle.

Answer

Tangent of an angle = Perpendicular/Base. For angle A, tan A = opposite side/adjacent side. It is a ratio and has no units.

Card 6Trigonometric Ratios

Define cotangent (cot) of an angle in a right triangle.

Answer

Cotangent of an angle = Base/Perpendicular. For angle A, cot A = adjacent side/opposite side. It is the reciprocal of tangent.

Card 7Trigonometric Ratios

Define secant (sec) of an angle in a right triangle.

Answer

Secant of an angle = Hypotenuse/Base. For angle A, sec A = hypotenuse/adjacent side. It is the reciprocal of cosine.

Card 8Trigonometric Ratios

Define cosecant (cosec) of an angle in a right triangle.

Answer

Cosecant of an angle = Hypotenuse/Perpendicular. For angle A, cosec A = hypotenuse/opposite side. It is the reciprocal of sine.

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Frequently Asked Questions

What are the important topics in Trigonometrical Ratios for ICSE Class 9 Mathematics?

Trigonometrical Ratios covers several key topics that are frequently asked in ICSE Class 9 board exams. Focus on the core concepts listed on this page and practise related questions to build confidence.

Start by understanding all key concepts. Practise previous year questions from this chapter. Revise formulas and definitions regularly. Use flashcards for quick revision before the exam.

There are 24 flashcards for Trigonometrical Ratios covering key definitions, formulas, and concepts. Use them daily for 10–15 minutes for best results.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.