mansehr

Area of triangle
$A = b*x/2$

Area of triangle with Herons formula.
$A = \sqrt{s(s-a)(s-b)(s-c)}$

s is the peremiter of the triangle divided by 2
$s = (a+b+c)/2$

mansehr

$\sqrt{(15-12)^2 + 8^2}$ = 5