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Year 9 Trigonometry (Finding Sides) Worksheet — Level 1 — Answers

Answer sheet with worked solutions for the Year 9 trigonometry worksheet.

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Year 9 · Mathematics · Trigonometry

Year 9 Trigonometry (Finding Sides) Worksheet — Level 1 — Answers

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Label the sides (opposite, adjacent, hypotenuse), choose the ratio (SOH CAH TOA), then solve.

1.In a right-angled triangle, the hypotenuse is 26 cm and one angle is 66°. Find the side opposite the 66° angle, to 1 decimal place.

Answer: 23.8 cm

  1. sin 66° = opposite ÷ hypotenuse
  2. opposite = 26 × sin 66°
  3. ≈ 23.8
2.In a right-angled triangle, the hypotenuse is 18 cm and one angle is 45°. Find the side opposite the 45° angle, to 1 decimal place.

Answer: 12.7 cm

  1. sin 45° = opposite ÷ hypotenuse
  2. opposite = 18 × sin 45°
  3. ≈ 12.7
3.In a right-angled triangle, the hypotenuse is 25 cm and one angle is 48°. Find the side opposite the 48° angle, to 1 decimal place.

Answer: 18.6 cm

  1. sin 48° = opposite ÷ hypotenuse
  2. opposite = 25 × sin 48°
  3. ≈ 18.6
4.In a right-angled triangle, the hypotenuse is 26 cm and one angle is 70°. Find the side opposite the 70° angle, to 1 decimal place.

Answer: 24.4 cm

  1. sin 70° = opposite ÷ hypotenuse
  2. opposite = 26 × sin 70°
  3. ≈ 24.4
5.In a right-angled triangle, the hypotenuse is 12 cm and one angle is 27°. Find the side opposite the 27° angle, to 1 decimal place.

Answer: 5.4 cm

  1. sin 27° = opposite ÷ hypotenuse
  2. opposite = 12 × sin 27°
  3. ≈ 5.4
6.In a right-angled triangle, the hypotenuse is 11 cm and one angle is 70°. Find the side opposite the 70° angle, to 1 decimal place.

Answer: 10.3 cm

  1. sin 70° = opposite ÷ hypotenuse
  2. opposite = 11 × sin 70°
  3. ≈ 10.3
7.In a right-angled triangle, the hypotenuse is 30 cm and one angle is 50°. Find the side opposite the 50° angle, to 1 decimal place.

Answer: 23 cm

  1. sin 50° = opposite ÷ hypotenuse
  2. opposite = 30 × sin 50°
  3. ≈ 23
8.In a right-angled triangle, the hypotenuse is 26 cm and one angle is 67°. Find the side opposite the 67° angle, to 1 decimal place.

Answer: 23.9 cm

  1. sin 67° = opposite ÷ hypotenuse
  2. opposite = 26 × sin 67°
  3. ≈ 23.9
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