In triangle ABC, A = 30 degrees, B = 45 degrees and a = 4. What is the length of b?
Answer and explanation
Correct answer: B. 4 root 2
- Step 1: Sine rule: a / sin A = b / sin B. Step 2. b = 4 x sin 45 / sin 30 = 4 x (root 2/2) / (1/2) = 4 root 2. Answer: 4 root 2. Why not the others: 2 root 2: That halves the correct value. 4: That would need A and B to be equal. 8: That is the circumdiameter, not the side b.
Practise more Trigonometric functions.
Free questions with an explanation for every one, and full timed CSAT Suneung mock tests.
More Trigonometric functions questions
- What is the period of the function y = 3 sin (2x)?
- What is the maximum value of the function y = 5 cos x + 12 sin x?
- If sin x = 3/5 and x is in the second quadrant, what is cos x?
- Find the value of sin 75 degrees x cos 15 degrees + cos 75 degrees x sin 15 degrees.
- Solve 2 sin x = 1 for x in the interval 0 to pi/2.
- What is the value of cos (2 pi/3)?