Success TutoringWorksheets

9th Grade Trigonometry (Finding Sides) Worksheet — Level 2 — Practice Set 4 — Answers

Answer sheet with worked solutions for the 9th Grade trigonometry worksheet.

Download answers PDFPrint answersBack to worksheet
Success TutoringWorksheetsAnswer sheet9th Grade · Mathematics · Trigonometry

9th Grade Trigonometry (Finding Sides) Worksheet — Level 2 — Practice Set 4 — Answers

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

1.In a right triangle, the hypotenuse is 10 cm and one angle is 68°. Find the side adjacent to the 68° angle, to 1 decimal place.

Answer: 3.7 cm

  1. cos 68° = adjacent ÷ hypotenuse
  2. adjacent = 10 × cos 68°
  3. ≈ 3.7
2.In a right triangle, the hypotenuse is 12 cm and one angle is 65°. Find the side opposite the 65° angle, to 1 decimal place.

Answer: 10.9 cm

  1. sin 65° = opposite ÷ hypotenuse
  2. opposite = 12 × sin 65°
  3. ≈ 10.9
3.In a right triangle, the hypotenuse is 30 cm and one angle is 36°. Find the side adjacent to the 36° angle, to 1 decimal place.

Answer: 24.3 cm

  1. cos 36° = adjacent ÷ hypotenuse
  2. adjacent = 30 × cos 36°
  3. ≈ 24.3
4.In a right triangle, the hypotenuse is 21 cm and one angle is 35°. Find the side opposite the 35° angle, to 1 decimal place.

Answer: 12 cm

  1. sin 35° = opposite ÷ hypotenuse
  2. opposite = 21 × sin 35°
  3. ≈ 12
5.In a right triangle, the hypotenuse is 18 cm and one angle is 38°. Find the side adjacent to the 38° angle, to 1 decimal place.

Answer: 14.2 cm

  1. cos 38° = adjacent ÷ hypotenuse
  2. adjacent = 18 × cos 38°
  3. ≈ 14.2
6.In a right triangle, the hypotenuse is 21 cm and one angle is 29°. Find the side opposite the 29° angle, to 1 decimal place.

Answer: 10.2 cm

  1. sin 29° = opposite ÷ hypotenuse
  2. opposite = 21 × sin 29°
  3. ≈ 10.2
7.In a right triangle, the side adjacent to a 20° angle is 23 m. Find the opposite side, to 1 decimal place.

Answer: 8.4 m

  1. tan 20° = opposite ÷ adjacent
  2. opposite = 23 × tan 20°
  3. ≈ 8.4
8.In a right triangle, the hypotenuse is 24 cm and one angle is 51°. Find the side adjacent to the 51° angle, to 1 decimal place.

Answer: 15.1 cm

  1. cos 51° = adjacent ÷ hypotenuse
  2. adjacent = 24 × cos 51°
  3. ≈ 15.1
Free worksheets at worksheets.successtutoring.com · © Success Tutoring · Free for personal and classroom use

Marking tips

  • Give credit for correct method even when the final answer slips — the working shows where the thinking went right.
  • For open-ended tasks, use the success criteria as a checklist rather than looking for one "right" answer.
  • Celebrate what went well first, then pick one thing to work on next.

Great work. Here's what to try next: