Inside a square with a perimeter of 4 cm, draw a circle with the side length of the square as its diameter. What is the circumference of this circle in centimeters.
在周长是4厘米的正方形内，以正方形的边长为直径画一个圆．这个圆的周长是多少厘米．
<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>