Master Li made a pair of cylindrical buckets without lids. Each bucket is 50cm high and the bottom diameter is 30cm. How much iron sheet is needed at least?
李师傅做了一对圆柱形无盖水桶，每个水桶高50cm，底面直径30cm，至少需要多少铁皮？
<gadget id="calculator">3.14 * 30 * 50</gadget>
<output>4_710</output>

<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225</gadget>
<output>706.5</output>

<gadget id="calculator">4_710 + 706.5</gadget>
<output>5_416.5</output>

<gadget id="calculator">5_416.5 * 2</gadget>
<output>10_833</output>

<result>10_833</result>