[etc]

function run():void {
	var g:Graphics = super.graphics;
 
	var w:Number = 50;
	var h:Number = 100;
	var cx:Number = 120;
	var cy:Number = 120;
	g.lineStyle(0, 0xFF0000, 1);
	g.moveTo(cx + w, cy);
 
	for (var i:uint = 0;i < 360;i++) {
		var a:Number = i / 180 * Math.PI;
		var x:Number = cx + w * Math.cos(a);
		var y:Number = cy + h * Math.sin(a);
 
		g.lineTo(x, y);
	}
 
	var sy:Number = 40;
 
	a = Math.asin(-sy / h);
	var ww:Number = w * Math.cos(a);
	trace(ww * 2);
 
	g.lineStyle(0, 0x00FF00, 1);
	g.moveTo(cx - ww, cy - sy);
	g.lineTo(cx + ww, cy - sy);
}
run();