Uncle workers of the greening team wear "cold clothes" for the newly planted small trees. He used a 24-meter straw rope to wrap 30 circles around the trunk of a small tree, and there was still 0.45 meters of grass rope left. What is the diameter of the trunk of this small tree in meters?
绿化队的工人叔叔为新栽的小树穿"防寒衣"．他用一条24米的草绳在一棵小树的树干上围了30圈，草绳还剩下0.45米，这棵小树的树干直径是多少米？
<gadget id="calculator">24 - 0.45</gadget>
<output>23.55</output>

<gadget id="calculator">23.55 / 30 / 3.14</gadget>
<output>0.25</output>

<result>0.25</result>