The hour hand of an analog clock is 5 cm long, what is the area swept by the hour hand in 3 hours?
一个指针式钟表的时针长5厘米，这根时针3小时扫过的面积是多少平方厘米．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">(1/4) * 3.14 * 25</gadget>
<output>19.625</output>

<result>19.625</result>