Year 11 Trigonometry (Finding Sides) Worksheet — Level 3 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 11 trigonometry worksheet.
Year 11 Trigonometry (Finding Sides) Worksheet — Level 3 — Practice Set 4 — Answers
Label the sides (opposite, adjacent, hypotenuse), choose the ratio (SOH CAH TOA), then solve.
1.In a right-angled triangle, the hypotenuse is 14 cm and one angle is 35°. Find the side adjacent to the 35° angle, to 1 decimal place.
Answer: 11.5 cm
- cos 35° = adjacent ÷ hypotenuse
- adjacent = 14 × cos 35°
- ≈ 11.5
2.In a right-angled triangle, the side adjacent to a 44° angle is 24 m. Find the opposite side, to 1 decimal place.
Answer: 23.2 m
- tan 44° = opposite ÷ adjacent
- opposite = 24 × tan 44°
- ≈ 23.2
3.In a right-angled triangle, the side adjacent to a 55° angle is 15 m. Find the opposite side, to 1 decimal place.
Answer: 21.4 m
- tan 55° = opposite ÷ adjacent
- opposite = 15 × tan 55°
- ≈ 21.4
4.In a right-angled triangle, the side adjacent to a 44° angle is 15 m. Find the opposite side, to 1 decimal place.
Answer: 14.5 m
- tan 44° = opposite ÷ adjacent
- opposite = 15 × tan 44°
- ≈ 14.5
5.In a right-angled triangle, the side adjacent to a 58° angle is 13 m. Find the opposite side, to 1 decimal place.
Answer: 20.8 m
- tan 58° = opposite ÷ adjacent
- opposite = 13 × tan 58°
- ≈ 20.8
6.In a right-angled triangle, the side adjacent to a 34° angle is 8 m. Find the opposite side, to 1 decimal place.
Answer: 5.4 m
- tan 34° = opposite ÷ adjacent
- opposite = 8 × tan 34°
- ≈ 5.4
7.In a right-angled triangle, the hypotenuse is 20 cm and one angle is 41°. Find the side opposite the 41° angle, to 1 decimal place.
Answer: 13.1 cm
- sin 41° = opposite ÷ hypotenuse
- opposite = 20 × sin 41°
- ≈ 13.1
8.In a right-angled triangle, the side adjacent to a 47° angle is 6 m. Find the opposite side, to 1 decimal place.
Answer: 6.4 m
- tan 47° = opposite ÷ adjacent
- opposite = 6 × tan 47°
- ≈ 6.4
Marking tips
- Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
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