Areas of Regular polygon

Question

So I tried to do this problem but when i checked my answer it was incorrect and I have no idea what I did wrong.

Here is the question

Find the area of each regular polygon with the given radius or apothem. If your

answer is not an integer, leave it in simplest radical form.

The shape is a square with a radius of 8 mm

Answer 1

For a square, the apothem is the line segment from its center at right angles to any of its sides. As such, it would equal one-half of a side length. The apothem is also the radius of the inscribed circle. The area of a square is s² where s is the side length. We have 8 = s/2, so s = 16 and the square's area = 16² = ____ mm².

Answer 2

The diameter is 16 mm

d = s√2

16 / √2 = s, s² = A

(16 / √2)² = A

256 / 4 = A