Hey there!
First, let's find s:
s = (5 + 6 + 7) /2 = 9
Second, let's plug in the numbers into the formula:
A =

Third, let's simplify the numbers to get one number under the square root:
A = [tex]\sqrt{216}
Fourth, we'll find the square root of 216 to get the area:
A = 14.697
Therefore, your answer is A.
Hope this helps!! :)