MENGHITUNG LUAS SEGITIGA SAMA KAKI PHP

<?php
$a = 10;
$t = 12;
$l = 1/2 * $a * $t;
echo "MENGHITUNG LUAS SEGITIGA SAMA KAKI <br>";
echo "====================================<br><br>";
echo "Alas = $a <br>";
echo "Tinggi = $t <br>";
echo "maka, Luas segitiga sama kaki = $l <br>";

?>