A 25.12-meter rope can wrap around the trunk of a tree exactly 10 times. What is the approximate radius of the cross-section of the trunk of this tree?
用一根25.12米的绳子正好可以绕一棵树的树干10圈，这棵树树干的横截面的半径大约是多少米？
<gadget id="calculator">25.12 / 10 / 3.14 / 2</gadget>
<output>0.4</output>

<result>0.4</result>