big tree is surrounded by a rope. The measured length of the rope is 62.8 cm. What is its cross-sectional area in square centimeters?
一棵大树用绳子围绕一周，测得绳长62.8厘米，它的截面面积是多少平方厘米．
<gadget id="calculator">62.8 / 3.14 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>