var ANGLE_TWO=ANGLE_ONE+DIFF,ANGLE_ONE_R=ANGLE_ONE*PI/180,ANGLE_TWO_R=ANGLE_TWO*PI/180;init({range:[[-11,31],[-10,10]],scale:20}),path([[5*cos(ANGLE_ONE_R),5*sin(ANGLE_ONE_R)],[0,0],[5*cos(ANGLE_TWO_R),5*sin(ANGLE_TWO_R)]]),arc([0,0],1,ANGLE_ONE,ANGLE_TWO),addMouseLayer(),graph.protractor=new Protractor([22,0])
DIFF^{\circ}
First, align the origin of the protractor with the vertex of the angle.
Next, rotate the protractor so that the 0^{\circ} mark lines up with one side of the angle.