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WAEC Mathematics 2011 Question 37

Question 37

Angles and Polygons

In the diagram, STUV is a straight line. ∠TSY = ∠UXY = 40° and ∠VUW = 110°. Calculate ∠TYW.

Diagram for this question
  1. A.150°
  2. B.140°
  3. C.130°
  4. D.120°
Show the answer and explanation

Answer: A (150°)

Explanation

∠TUX = 180° − 110° = 70°. In ΔTUX, ∠UTX = 180° − 70° − 40° = 70°, so ∠STY = 110°. In ΔSTY, ∠SYT = 180° − 40° − 110° = 30°, so ∠TYW = 180° − 30° = 150°.