A bisector is a line which cuts another line exactly in half. An angle bisector cuts an angle into two angles of equal size. It can be constructed using a ruler and a pair of compasses.

In this case use the length 8 cm, and the two angles 40° and 50°. Use a ruler to draw a line from the end of the line through the dot and label the angle 40°. TIP: you won't know the exact ...