Answer:
≈20.56
Explanation:
Since the total length of a side is 6 and the small bit is 2, the radius of the curve is 2. The curves are all 90° meaning they add up to one full circle, so you could just find the circumference of the circle with a radius of 2 plus the lengths between the curves.
Circumference = 2π(2) ≈ 12.57
Perimeter = 12.57 + 4(2) = 20.56