Flash CS3 - Circular Motion - Rotating Square

ActionScript Code:

stage.frameRate=30;
//draw square
var square:Shape = new Shape();
square.graphics.beginFill(0xFF6600,1);
square.graphics.drawRect(-25,-25,50,50);
square.graphics.endFill();
square.x=stage.stageWidth/2;
square.y=stage.stageHeight/2;
addChild(square);
//draw circle
var circle:Shape = new Shape();
circle.graphics.lineStyle(1,0x00FFCC);
circle.graphics.drawCircle(0,0,100);
circle.x=stage.stageWidth/2;
circle.y=stage.stageHeight/2;
addChild(circle);
//Animate SquaRE
var radius:Number = 100;
var speed:Number = .1;
var xcenter:Number = square.x;
var ycenter:Number = square.y;
var degree:Number = 0;
stage.addEventListener(Event.ENTER_FRAME,myFunction);
function myFunction(e:Event):void {
 degree += speed;
 square.x = xcenter+Math.cos(degree)*radius;
 square.y = ycenter+Math.sin(degree)*radius;
}