Answer
$14\bar{0}~m^2, \ 54.0\ m$
Work Step by Step
For the equilateral triangle of side $18 \ m$, we have $s=\frac{3\times18}{2}=27\ m.$
Then the area is given by Heron’s formula as follows:
$$
Area= \sqrt{s(s-a)^3}=\sqrt{27(27-18)^3}=140.29\ m^2\approx 14\bar{0}~m^2
.$$
The perimeter of a triangle is the sum of the lengths of the sides, so we have:
$$perimeter= 3\times18=54.0\ m
.$$
