The answer is B. 16.1 square meters
The region has triangular shape. To calculate the area of the triangle when three sides are known, we will use the Heron's formula:
A = √s(s-a)(s-b)(s-c)
where:
A - the area of the triangle
a, b, and c - the sides of the triangle
s - half of the triangle's perimeter: s = (a+b+c)/2
It is given:
a = 13 m
b = 5 m
c = 9 m
First, calculate s:
s = (a+b+c)/2 = (13+5+9)/2 = 13.5
Now, it is easy to calculate the area:
A = √s(s-a)(s-b)(s-c) = √13.5(13.5-13)(13.5-5)(13.5-9) = √13.5×0.5×8.5×4.5 = √258.19 = 16.07 ≈ 16.1