The minute hand of a quartz clock is 10cm long, and the area swept by the minute hand is 157cm**2. How many minutes does the minute hand go?
一个石英钟的分针长10cm，分针旋转扫过的面积是157cm**2．分针走了多少分钟？
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">157 / 314</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(1/2) * 60</gadget>
<output>30</output>

<result>30</result>