WAEC Mathematics 2007 Question 20

Question 20

Triangles and Quadrilaterals

Find the value of x in the diagram.

Diagram for this question
  1. A.281°
  2. B.269°
  3. C.201°
  4. D.179°
Show the answer and explanation

Answer: A (281°)

Explanation

Through the vertex of x draw a line parallel to the two parallel lines. The upper arm makes 45° with it (vertically opposite the 45° and alternate angles) and the lower arm makes 34°, so the angle on the left is 45° + 34° = 79°. The reflex angle x = 360° − 79° = 281°.