var a = (angle -90 )* ((2*Math.PI)/360); var y1 = length * Math.sin(a); var x1 = length * Math.cos(a); this.moveTo(startx,starty); this.lineTo(startx+x1, starty+y1); this.lineTo(startx,starty+y1); this.lineTo(startx,starty); this.strokeStyle = 0; this.lineWidth = 1; this.stroke();