triangulo.php

<?php

class Triangulo
{
    private $base;
    private $altura;
    private $area;

    //Getters:
    public function getAltura() {
        return $this->altura;
    }

    public function getBase() {
        return $this->base;
    }

    public function getArea() {
        return $this->area;
    }

    //Setters:
    public function setAltura($a) {
        $this->altura = $a;
    }

    public function setBase($b) {
        $this->base = $b;
    }

    public function setArea($ar) {
        $this->area = $ar;
    }

    public function area(){
        return ($this->getBase() * $this->getAltura()/2);
    }

    public function imprimir(){
        print "Altura: ".$this->getAltura()."\n";
        print "Base: ".$this->getBase()."\n";
        print "Area: ".$this->area()."\n";
    }
}

$area = new Triangulo();
$area->setAltura(6);
$area->setBase(3);
$area->imprimir(); 

?>