Answer
$158\ m^2, \ 60.8\ m$
Work Step by Step
Since the right triangle is isosceles, then the legs are equal.
The area is given by
$$
Area= \frac{1}{2} base \times height=\frac{1}{2}\times17.8\times 17.8=158.42\ m^2\approx 158~m^2
.$$
The perimeter of a triangle is the sum of the lengths of the sides:
$$perimeter=17.8+17.8+17.8\sqrt{2}=60.8\ m
.$$
Where we used the Pythagorean theorem to find the hypotenuse:
$c^2=a^2+b^2$
$c=\sqrt{17.8^2+17.8^2}=17.8\sqrt{2}$
