Answer: Approximately 137.74977 square units
===================================================
Explanation:
We can use Heron's formula to find the area of a triangle when given all three sides.
First we need the semiperimeter
s = semiperimeter
s = (perimeter)/2
s = (a+b+c)/2
s = (28+28+10)/2
s = 33
Now we can compute the area of the triangle.
[tex]A = \sqrt{s(s-a)(s-b)(s-c)}\\\\A = \sqrt{33(33-28)(33-28)(33-10)}\\\\A = \sqrt{18975}\\\\A \approx 137.74977\\\\[/tex]
