Find the area of a circle and the length of its circumference if the side of the square described around it is 6 cm.

1. It turns out that we have a circle inscribed in a square, by the property of a square, the radius of the circle is equal to half of the side of the square:
r = a / 2 = 6/2 = 3 cm.
2. The area of a circle by a known radius is found from the expression:
S = π * r² = π * 3² = 9π = 28.26 cm.
3. The length of the circle can be determined by the formula:
l = 2 * π * r = 2 * π * 3 = 6π = 18.84 cm.
Answer: the area of the circle is 28.26 cm, the circumference that limits it is 18.84 cm.