The minute hand of a clock is 5 cm long. From 7 am to 8 am, what is the area swept by the minute hand in square centimeters?
某钟表的分针长5厘米，从上午7时到上午8时，分针扫过的面积是多少平方厘米．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>