Answer
$58.7 \ m, \ 159\ m^2.$
Work Step by Step
Since the perimeter of a triangle is the sum of the lengths of the sides, then we have
$$perimeter=16.5+21.9+20.3=58.7 \ m
.$$
Also, the area is given by
$$
Area= \frac{1}{2} base \times hight=\frac{1}{2}\times20.3\times 15.7=159.355\ m^2\approx 159 ~m^2
.$$
