Five garden workers drove lawn mowers to mow a semi-circular lawn with a circumference of 257 meters at the same time, and the mowing was completed in 3.14 hours. If each worker drives a lawn mower with the same work efficiency, how many hours does it take for a worker to drive a lawn mower to mow a lawn of 500 square meters? (π takes 3.14)
五名园林工人分别驾驶割草机同时给一个周长是257米的半圆形草坪割草，3.14小时割完．若每名工人驾驶割草机割草的工作效率相同，则照这样计算，一名工人驾驶割草机给500平方米的草坪割草需要多少小时．(π取3.14)
<gadget id="calculator">3.14 + 2</gadget>
<output>5.14</output>

<gadget id="calculator">257 / 5.14</gadget>
<output>50</output>

<gadget id="calculator">50 ** 2</gadget>
<output>2_500</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 2_500 * (1/2)</gadget>
<output>3_925</output>

<gadget id="calculator">3_925 / 5 / 3.14</gadget>
<output>250</output>

<gadget id="calculator">500 / 250</gadget>
<output>2</output>

<result>2</result>