A pillar with a circular cross-section can be wound around the pillar four times with a rope 50.24 meters long. What is the cross-sectional area of this pillar?
一根横截面是圆形的柱子，用50.24米长的绳子正好可以绕柱子4圈，这根柱子的横截面的面积是多少？
<gadget id="calculator">50.24 / 4 / 3.14 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<result>12.56</result>