What is the perimeter of a square if the radius of the circle that touches each side of this square is 3 cm?

If the circle touches each side of the square, then it turns out that it is inscribed in it. In this case, the side of the square will be equal to the double radius or diameter of the inscribed circle:
3 x 2 = 6 (cm).
Then the perimeter of the square is quite easy to calculate. It is equal to the sum of the lengths of the four sides of the square:
6 + 6 + 6 + 6 = 24 (cm).
Answer: the perimeter of the declared square is 24 cm.