Draw a third parallel line a∘=35∘"(Vertically opposite angles are the same) a∘=b∘=35∘ (Alternate angles are the same) 140∘+d∘=180∘ (Sum of angles on a straight line is 180°) d∘=180∘−140∘ d∘=40∘ c∘=d∘=40∘ (Alternate angles are the same) b∘+c∘+x∘=360∘ (Sum of angles in a circle is 360°) 35∘+40∘+x∘=360∘ 75∘+x∘=360∘ x∘=360∘−75∘ x∘=285∘