passwella.
Menu

JAMB Mathematics 1990 Question 40

Question 40

Trigonometry

In the figure above, YX̂Z = 30°, XŶZ = 105° and XY = 8cm. Calculate YZ.

Diagram for this question
  1. A.16√2cm
  2. B.8√2cm
  3. C.4√2cm
  4. D.2√2cm
Show the answer and explanation

Answer: C (4√2cm)

Explanation

Angle Z = 180° − 30° − 105° = 45°. By the sine rule, YZ/sin 30° = 8/sin 45°, so YZ = 8 × ½ ÷ (√2/2) = 4√2cm.