A certain type of washbasin produced by the enamel factory is punched out of a circular iron sheet with a diameter of 0.5 meters. If 800 such washbasins are produced every day, how many iron sheets are needed?
搪瓷厂生产的某种型号脸盆是用直径为0.5米的圆形铁皮冲成的，如果每天生产这种脸盆800个，需要多少铁皮？
<gadget id="calculator">0.5 / 2</gadget>
<output>0.25</output>

<gadget id="calculator">0.25 ** 2</gadget>
<output>0.0625</output>

<gadget id="calculator">3.14 * 0.0625 * 800</gadget>
<output>157</output>

<result>157</result>