text: /**
   * Function to calculate area of circle
   * and send back the response to client
   * @param {*} radius 
   * @param {*} res 
   */
  
  
  function getAreaOfCircle(radius, res){
      const areaOfCircle = Math.PI * radius * radius;
         return areaOfCircle
  };
  module.exports.getAreaOfCircle = getAreaOfCircle;
  
  function getVolumeOfSphere(radius, res){
      const volumeOfSphere = 4/3 * Math.PI * radius * radius * radius;
      return volumeOfSphere
  };
  module.exports.getVolumeOfSphere = getVolumeOfSphere;
  
  function getSurfaceAreaOfSphere(radius, res){
      const surfaceAreaOfSphere = 4 * Math.PI * radius * radius;
      return surfaceAreaOfSphere
  };
  module.exports.getSurfaceAreaOfSphere = getSurfaceAreaOfSphere;
  
  
  