The hour hand of a clock is 20 cm long. How many cm does the tip of the hour hand move after 3 hours?
一个钟的时针长20cm，经过3小时，时针针尖走了多少cm．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3.14 * 10 * (1/4)</gadget>
<output>7.85</output>

<result>7.85</result>