passwella.
Menu

WAEC Further Mathematics 2009 Question 31

Question 31

Vectors

Calculate, correct to the nearest degree, the angle between the vectors (13, 1) and (1, 4)

  1. A.58°
  2. B.72°
  3. C.74°
  4. D.87°
Show the answer and explanation

Answer: B (72°)

Explanation

Dot product = 13 + 4 = 17. cos θ = 17/(√170 × √17) = 1/√10 ≈ 0.316, so θ ≈ 72°.