A cylinder with a base circumference of 6.28 decimeters is cut vertically along its diameter to obtain a square cross-section. What is the area of this cross section?
将一个底面周长为6.28分米的圆柱体沿着它的直径垂直切开，得到一个正方形的截面．这一个截面的面积是多少？
<gadget id="calculator">6.28 / 3.14</gadget>
<output>2</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>