Question 2(a) was also popular among the candidates and their performance in it was fair. Some of the errors noticed from their responses indicated that many of the candidates could not recognize adjacent angles on a straight line as well as the alternate angle CAB.
In the question 2 (b), many candidates took (134+ n)o as the sum of the interior angles. Some others who were able to recognize it as an interior angle, got the required quadratic equation but could not go further. If (134 + n)o is an interior angle, then the exterior angle = 180 o – (134 + n) o = (46-n) o . Since the polygon is regular, then the sum of its exterior angle = n x one exterior angle, where n = number of sides. Therefore, sum of the exterior angle = n(46 - n)o. But sum of exterior angle = 360o, therefore n(46-n) = 360o or n2 – 46n + 360 = 0, i.e.
(n-10)(n-36) = 0 which gives n = 10, 36. The polygon has either 10 or 36 sides.
