The hour hand of a wall clock is 5 cm long and the minute hand is 8 cm long. From 6:00 am to 12:00 noon, what is the area "swept" by the hour hand in square centimeters?
一只挂钟的时针长5cm，分针长8cm，从早上6时到中午12时，时针"扫过"的面积是多少平方厘米．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * 25 * (1/2)</gadget>
<output>39.25</output>

<result>39.25</result>