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WAEC Mathematics 2014 Question 20

Question 20

Angles and Polygons

In the diagram, PQR is a straight line, (m + n) = 120° and (n + r) = 100°. Find (m + r).

Diagram for this question
  1. A.110°
  2. B.120°
  3. C.140°
  4. D.160°
Show the answer and explanation

Answer: C (140°)

Explanation

m + n + r = 180°. Adding the two given sums: m + 2n + r = 220°, so n = 40° and m + r = 140°.