WAEC Mathematics 2021 Paper

Concept:Angles on a straight line add up to $180^\circ$, and corresponding angles formed by a transversal across parallel lines are equal.Explanation:Consider the angle adjacent to $35^\circ$ on the straight line.$35^\circ + m = 180^\circ$$m = 180^\circ - 35^\circ = 145^\circ$Since this angle and angle $x$ are corresponding angles, $x = 145^\circ$.Now consider the angle adjacent to $110^\circ$ on the other straight line.$110^\circ + n = 180^\circ$$n = 180^\circ - 110^\circ = 70^\circ$Since this angle and angle $y$ are corresponding angles, $y = 70^\circ$.Therefore,$x + y = 145^\circ + 70^\circ = 215^\circ$.Answer:$x + y = 215^\circ$, so the correct option is A.