# Khan/khan-exercises

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 Measuring angles
randRange(0, 359) 10 * randRange(1, 18)

Measure this angle in degrees.

var LENGTH = 9; 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, 15], [-10, 10] ], scale: 20 }); style({ stroke: BLUE, arrows: "-->" }); line([0, 0], [LENGTH * cos(ANGLE_ONE_R), LENGTH * sin(ANGLE_ONE_R)]); line([0, 0], [LENGTH * cos(ANGLE_TWO_R), LENGTH * sin(ANGLE_TWO_R)]); style({ stroke: BLUE, arrows: null }); arc([0, 0], 1, ANGLE_ONE, ANGLE_TWO); addMouseLayer(); graph.protractor = protractor([14, -8]); graph.showOrigin = function() { graph.protractor.moveTo( 0, 0 ); }; graph.showCorrect = function() { graph.showOrigin(); graph.protractor.rotateTo(540 - ANGLE_ONE - DIFF); };
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.showCorrect(); label([10 * cos(toRadians(ANGLE_ONE)), 10 * sin(toRadians(ANGLE_ONE))], "\\pink{" + DIFF + "^{\\circ}}" );

The angle is DIFF degrees.