class Meter {
    	private $meters = 0.0;
    	
    	public function __construct($meters) {
    		if(is_numeric($meters)) {
    			$this->setMeters($meters);
    		} else {
    			throw new Exception("Input should be numeric.");
    		}
    	}
    	
    	protected function getMeters() {
    		return $this->meters;
    	}
    	
    	private function setMeters($meters = 0.0) {
    		$this->meters = $meters;
    	}
		
	        public function getAsDecimeters() {
    		return $this->getMeters() * 10;
    	}
		
    	public function getAsFeet() {
    		return $this->getMeters() * (1 / 0.3048);
    	}
		public function getAsCentimeters() {
    		return $this->getMeters() * 100;
    	}
    }