If the hour hand of a clock is 10 cm long, what is the area in square centimeters that the hour hand travels in 12 hours?
一个时钟的时针长10厘米，12小时时针走过的面积是多少平方厘米．
<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<result>314</result>