The hour hand of the table clock is 4 cm long, and the minute hand is 5 cm long. They rotate (1/4) circles respectively. How many square centimeters are the difference between the areas they sweep?
台钟的时针长4厘米，分针长5厘米，分别转动(1/4)圈，它们所扫过的面积相差多少平方厘米？
<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">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">25 - 16</gadget>
<output>9</output>

<gadget id="calculator">(1/4) * 3.14 * 9</gadget>
<output>7.065</output>

<result>7.065</result>