To make a cylindrical metal bucket without a cover, the diameter of the bottom surface is 50cm, and the height is 60cm. How much metal is needed to make 5 such buckets? (neglected at joints)
做一个无盖的圆柱形铁皮水桶，底面直径50cm，高是60cm，做这样的5个水桶大约需要多少铁皮？(接头处忽略不计)
<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">25 ** 2</gadget>
<output>625</output>

<gadget id="calculator">3.14 * 625</gadget>
<output>1_962.5</output>

<gadget id="calculator">942 + 1_962.5</gadget>
<output>2_904.5</output>

<gadget id="calculator">2_904.5 * 5</gadget>
<output>14_522.5</output>

<result>14_522.5</result>