A 40-meter-long rope is used to wrap 8 times around the trunk of a big tree, and the result is an additional 2.32 meters. What is the approximate diameter of the trunk of this big tree?
用一根长40米的绳子绕一棵大树的树干8圈，结果还多下2.32米，这棵大树的树干直径大约是多少米？
<gadget id="calculator">40 - 2.32</gadget>
<output>37.68</output>

<gadget id="calculator">37.68 / 8</gadget>
<output>4.71</output>

<result>4.71</result>