What is the area of A is 7.7ft and B is 5.2ft and C is 9.29 and this is a triangle

So basically I want to know the answer

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.