randRange(0, 359) 10 * randRange(1, 18)
Measure this angle in degrees.
var ANGLE_TWO = ANGLE_ONE + DIFF; var ANGLE_ONE_R = ANGLE_ONE * PI / 180; var 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 = protractor([14, -8]);
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.

graph.protractor.moveTo( 0, 0 ); graph.protractor.rotateTo( 540 - ANGLE_ONE - DIFF ); label( [ 9 * cos( toRadians( ANGLE_ONE ) ), 9 * sin( toRadians( ANGLE_ONE ) ) ], "\\color{" + PINK + "}{" + DIFF + "^{\\circ}}" );

The angle is DIFF degrees.