If a minute hand is 2 cm long, what is the area covered by it in 15 minutes?
一根分针长2厘米，15分钟所扫过的面积是多少．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3.14 * 4 * (1/4)</gadget>
<output>3.14</output>

<result>3.14</result>