Question 19
Angelo drew two lines meeting at a right angle. What is the smallest number of extra lines he could draw inside his right angle, as shown, so that for any of the values $10^\circ,20^\circ,30^\circ,40^\circ,50^\circ,60^\circ,70^\circ,80^\circ$, a pair of lines can be chosen with the angle between them equal to that value? 