The hour hand with a length of 3 cm is from 7 o'clock to 11 o'clock, what is the area swept by the hour hand?
长为3厘米的时针从7点到11点，时针扫过的面积是多少．
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">120 / 360</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3.14 * 9 * (1/3)</gadget>
<output>9.42</output>

<result>9.42</result>