Q1
What is sine (sin) of an angle?
AOpposite ÷ hypotenuse
BAdjacent ÷ hypotenuse
COpposite ÷ adjacent
DHypotenuse ÷ opposite
ICSEClass 9 (ICSE)MathematicsCh 22 · Topic 2
Practice and Revision - Trigonometrical Ratios
Let us practise and revise what we learned about trigonometrical ratios. Trigonometric ratios - sine, cosine, and tangent - relate the angle
Core concept
Sine (sin) of an angle equals the opposite side divided by the hypotenuse, cosine (cos) equals the adjacent side divided by the hypotenuse.
How it works
Tangent (tan) of an angle equals the opposite side divided by the adjacent side, or equivalently, sin divided by cos.
Why it matters
These ratios help us find unknown sides or angles in right triangles when we know some of the other measurements.
Key detail
Trigonometric ratios have wide applications in fields like engineering, architecture, navigation, and astronomy for measuring distances and heights.
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Quick notes
• Sine = opposite ÷ hypotenuse.
• Cosine = adjacent ÷ hypotenuse.
• Tangent = opposite ÷ adjacent (or sin ÷ cos).
• These relate angles to side ratios.
• They find unknown sides or angles.
• This requires knowing some other measurements.
• Trigonometry is used in engineering and navigation.
• It helps measure distances and heights.