function circle(radius)  
{  
    this.radius = radius;  
  // area method  
    this.area = function ()   
    {  
        return Math.PI * this.radius * this.radius;  
    };  
  // perimeter method  
    this.perimeter = function ()  
    {  
        return 2*Math.PI*this.radius;  
    };  
}  
var c = new circle(3);  
console.log('Area =', c.area().toFixed(2));  
console.log('perimeter =', c.perimeter().toFixed(2)); 