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WAEC Mathematics 1996 Question 37

Question 37

Angles and Polygons

Two angles (a + 31)° and (b − 49)° are adjacent angles on a straight line. Which of the following is true

  1. A.a + b = 198°
  2. B.a + b = 180°
  3. C.a + b = 162
  4. D.a + b = 100°
  5. E.a + b = 80°
Show the answer and explanation

Answer: A (a + b = 198°)

Explanation

Adjacent angles on a straight line add to 180°: a + 31 + b − 49 = 180, so a + b − 18 = 180 and a + b = 198°.