A kind of part is made of a circular iron sheet with a radius of 3 cm. To produce 100 pieces of this kind of part, how many square centimeters of this iron sheet are needed?
一种零件是用半径3厘米的圆形铁皮制成的，生产这种零件100个，需要这种铁皮多少平方厘米？
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 100</gadget>
<output>2_826</output>

<result>2_826</result>