The students in the biology group wanted to measure the cross-sectional area of a hundred-year-old banyan tree. They measured that the circumference of the trunk was 6.28 meters. What is the cross-sectional area of this tree in square meters?
生物小组同学要测量一棵百年大榕树的横截面积，他们量得树干的周长是6.28米，这棵树的横截面积是多少平方米？
<gadget id="calculator">6.28 / 2 / 3.14</gadget>
<output>1</output>

<gadget id="calculator">1 ** 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 1</gadget>
<output>3.14</output>

<result>3.14</result>