The minute hand of a clock is 5 cm long. From 1 o'clock to 2 o'clock, what is the area swept by the tip of the minute hand in cm**2.
一个钟表的分针长5cm，从1时到2时，分针针尖扫过的面积是多少cm**2．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

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

<result>78.5</result>