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Year 9 Trigonometry (Finding Sides) Worksheet — Level 2 — Answers

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

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Success TutoringWorksheetsAnswer sheetYear 9 · Mathematics · Trigonometry

Year 9 Trigonometry (Finding Sides) Worksheet — Level 2 — Answers

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

1.In a right-angled triangle, the hypotenuse is 8 cm and one angle is 29°. Find the side adjacent to the 29° angle, to 1 decimal place.

Answer: 7 cm

  1. cos 29° = adjacent ÷ hypotenuse
  2. adjacent = 8 × cos 29°
  3. ≈ 7
2.In a right-angled triangle, the hypotenuse is 8 cm and one angle is 20°. Find the side adjacent to the 20° angle, to 1 decimal place.

Answer: 7.5 cm

  1. cos 20° = adjacent ÷ hypotenuse
  2. adjacent = 8 × cos 20°
  3. ≈ 7.5
3.In a right-angled triangle, the hypotenuse is 8 cm and one angle is 43°. Find the side adjacent to the 43° angle, to 1 decimal place.

Answer: 5.9 cm

  1. cos 43° = adjacent ÷ hypotenuse
  2. adjacent = 8 × cos 43°
  3. ≈ 5.9
4.In a right-angled triangle, the hypotenuse is 11 cm and one angle is 34°. Find the side adjacent to the 34° angle, to 1 decimal place.

Answer: 9.1 cm

  1. cos 34° = adjacent ÷ hypotenuse
  2. adjacent = 11 × cos 34°
  3. ≈ 9.1
5.In a right-angled triangle, the hypotenuse is 28 cm and one angle is 36°. Find the side adjacent to the 36° angle, to 1 decimal place.

Answer: 22.7 cm

  1. cos 36° = adjacent ÷ hypotenuse
  2. adjacent = 28 × cos 36°
  3. ≈ 22.7
6.In a right-angled triangle, the side adjacent to a 28° angle is 6 m. Find the opposite side, to 1 decimal place.

Answer: 3.2 m

  1. tan 28° = opposite ÷ adjacent
  2. opposite = 6 × tan 28°
  3. ≈ 3.2
7.In a right-angled triangle, the hypotenuse is 14 cm and one angle is 31°. Find the side opposite the 31° angle, to 1 decimal place.

Answer: 7.2 cm

  1. sin 31° = opposite ÷ hypotenuse
  2. opposite = 14 × sin 31°
  3. ≈ 7.2
8.In a right-angled triangle, the hypotenuse is 7 cm and one angle is 39°. Find the side adjacent to the 39° angle, to 1 decimal place.

Answer: 5.4 cm

  1. cos 39° = adjacent ÷ hypotenuse
  2. adjacent = 7 × cos 39°
  3. ≈ 5.4
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