Draw a Straight line 
Take a point on it.
Make a complete 180° arc.
Mark two arcs of 120° and 180°
Bisect them and you will get the 150°
Draw a dotted line joining the Point and the 150° mark.
Now again Bisect the 150° mark and 180°  mark , to get the 165° mark.
Make a line joining the 165° mark and the point to get the required angle

10 4 10