Trigonometry (2D & 3D) is one of 9 topics in the Grade 12 Technical Mathematics CAPS syllabus, covered across 3 lessons on Study Vault. Below are real practice questions from this topic with full worked answers.
Sample practice questions
Easy
1. State the Sine Rule for a triangle with sides a, b, c opposite angles A, B, C.
Answer: a/sin(A) = b/sin(B) = c/sin(C) — The Sine Rule states a/sin(A) = b/sin(B) = c/sin(C).
Easy
2. Which rule should be used to find a missing side when two sides and the included angle of a triangle are known?
The Cosine Rule
The Sine Rule only
The Area Rule only
Basic SOH CAH TOA only, regardless of the triangle
Answer: The Cosine Rule — The Cosine Rule (a^2=b^2+c^2-2bc.cos(A)) is used when two sides and the included angle are known, to find the third side.
Medium
3. Use the Area Rule to find the area of a triangle with sides a=6, b=9 and included angle C=40 degrees. Give your answer to 2 decimal places. (sin40 degrees = 0.643)
Answer: 17.36 — Area = (1/2)ab.sin(C) = 0.5 x 6 x 9 x 0.643 = 17.36 (2 d.p.).
