Lingkaran

<?php

class Lingkaran {
    private $jariJari;
    private $phi = 3.14;
    
    public function keliling($jariJari) {
        $this->jariJari = $jariJari;
        $keliling = $this->phi * 2 * $this->jariJari;
        
        return $keliling;
    }
    
    public function luas($jariJari) {
        $this->jariJari = $jariJari;
        $luas = $this->phi * ($this->jariJari * $this->jariJari);
        
        return $luas;
    }
}

$lingkaranSatu = new Lingkaran();
$jariJari = 7;
echo "Keliling Lingkaran = {$lingkaranSatu->keliling($jariJari)}\n";
echo "Luas Lingkaran = {$lingkaranSatu->luas($jariJari)}\n";