Given: ∠ROS = 90° ∠POS = 35° Calculation: Sum of angles on a straight line is 180° ⇒∠ROS+∠ROQ=180° ⇒∠ROQ=180°−90 ° ⇒∠ROQ=90° ⇒∠POS+∠POQ=180° ⇒∠POQ=180°−35° ⇒∠POQ=145° ⇒∠POQ−∠ROQ=145°−90° ∴∠POQ−∠ROQ=55° The correct option is 1 i.e. 55° Sum of angles on a straight line is 180°