passwella.
Menu

WAEC Mathematics 2010 Question 3

Question 3

Triangles and Quadrilaterals

In the diagram, ∠PSR = 22°, ∠SPQ = 58° and ∠PQR = 41°. Calculate the obtuse angle QRS.

Diagram for this question
  1. A.99°
  2. B.100°
  3. C.121°
  4. D.165°
Show the answer and explanation

Answer: C (121°)

Explanation

Extend SR to meet PQ at X. In triangle PSX the exterior angle at X is 22° + 58° = 80°. In triangle XRQ the obtuse angle QRS is an exterior angle: 80° + 41° = 121°.