soal_ketiga

<?php

interface Segitiga {
	public function calculate();
}

class Keliling implements Segitiga
{
	private $a;
	private $b;
	private $c;

	public function __construct($a, $b, $c) {
		$this->a = $a;
		$this->b = $b;
		$this->c = $c;
	}

	public function calculate() {
		return $this->a + $this->b + $this->c;
	}
}

class Luas implements Segitiga
{
	private $a;
	private $b;

	public function __construct($a, $b) {
		$this->a = $a;
		$this->b = $b;
	}

	public function calculate() {
		return ($this->a * $this->b) / 2;
	}
}

$keliling = new Keliling(10, 20, 30);
$luas = new Luas(10, 30);

echo 'Keliling: '.$keliling->calculate();
echo PHP_EOL;
echo 'Luas: '.$luas->calculate();
echo PHP_EOL;