Respuesta :

RonPayne
First find half of the perimeter of the triangle: s = (a + b + c) / 2 = 11.095

Then the area is:

A = Square Root [11.095 (11.095 - 7.7)(11.095 - 5.2)(11.095 - 9.29)] = 20.01999895 or 20.02 square feet rounded to 2 decimal places.