A rope with a length of 15.7 meters is wound around the trunk of a big tree exactly 10 times. What is the approximate radius of the cross section of the trunk of this big tree in meters?
一根长15.7米的绳子绕一棵大树的树干正好绕10圈，这棵大树树干的横截面半径约是多少米？
<gadget id="calculator">15.7 / 10</gadget>
<output>1.57</output>

<gadget id="calculator">2 * 3.14</gadget>
<output>6.28</output>

<gadget id="calculator">1.57 / 6.28</gadget>
<output>0.25</output>

<result>0.25</result>