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Example 7 - Chapter 8 Class 10 Introduction to Trignometry
Last updated at April 16, 2024 by Teachoo
Trignometric ratios of Specific Angles - Evaluating
Chapter 8 Class 10 Introduction to Trignometry
Concept wise
- Finding sin cos tan
- Finding sin cos when sides of a triangle are given
- Finding ratios when other ratios are given
- Finding values of expressions
- Proving
-
Trignometric ratios of Specific Angles - Evaluating
- Trignometric ratios of complementry angles
- Expressing ratios in other ratios
- Evaluating using Trignometric Identities
Transcript
Example 7 In Δ PQR, right-angled at Q (see Fig. ), PQ = 3 cm and PR = 6 cm. Determine ∠ QPR and ∠ PRQ. Now, sin R = (𝑠𝑖𝑑𝑒 𝑜𝑝𝑝𝑜𝑠𝑖𝑡𝑒 𝑡𝑜 𝑎𝑛𝑔𝑙𝑒 𝑅)/𝐻𝑦𝑝𝑜𝑡𝑒𝑛𝑢𝑠𝑒 sir R = 𝑃𝑄/𝑃𝑅 sir R = 𝟑/𝟔 sin R = 1/2 sin R = sin 30° R = 30° So, ∠ PRQ = 30° Now, By angle sum property of triangle ∠ P + ∠ Q + ∠ R = 180° ∠ P + 90° + 30° = 180° ∠ P + 120° = 180° ∠ P = 180° − 120° ∠ P = 60° So, ∠ QPR = 60° Hence , ∠ PRQ = 30° ∠ QPR = 60°
