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JAMB Mathematics 1979 Question 40

Question 40

Angles and Polygons

PQ is parallel to RS. Calculate the value of x

Diagram for this question
  1. A.20°
  2. B.40°
  3. C.60°
  4. D.80°
  5. E.100°
Show the answer and explanation

Answer: B (40°)

Explanation

The angles where the lines cross are 100° and 80°. <S = <P = 60° (alternate angles), so in the lower triangle x = 180° − 80° − 60° = 40°.