Answer
$15.6~cm^2, \ 18.0\ cm$
Work Step by Step
For an equilateral triangle of side $6 \ cm$, we have
$s=\frac{3\times6}{2}=9\ cm.$
Then the area is given by Heron’s formula as follows:
$$
Area= \sqrt{s(s-a)^3}=\sqrt{9(9-6)^3}=15.58\ cm^2\approx 15.6~cm^2
.$$
The perimeter of a triangle is the sum of the lengths of the sides:
$$perimeter= 3\times6=18.0\ cm
.$$
