1. Measuring Angles

7. You can use the protractor for drawing angles Let’s draw an angle of 120º With the ruler draw a line segment 120º Take away the protractor Place the protractor in this way: The centre of the protractor in one end of the line segment The line through the zeros on top of the line segmen t And draw a mark at 120 º 0 0 120 centre Draw a line through the centre and the mark

8. Classifying angles Right : 90º Acute : less than 90º Obtuse : more than 90º and less than 180º Straight : 180º Reflex : more than 180° but less than 360°

9. Supplementary angles 180º Supplementary angles add up to 180º

10. Complementary Angles Complementary angles add up to 90º 90 º