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 length of this new side yet so draw it a bit longer than you think you ...

A line drawn to cut another line or angle in half is a bisector. The path of a point that moves according to a certain rule is a locus. The plural of locus is loci. Practise these constructions ...