A cylindrical iron drum with a bottom diameter of 4dm and a height of 5dm. If the water contained in the iron bucket accounts for (1/4) of the bucket, how many liters of water are there?
一个底面直径是4dm的圆柱形无盖的铁桶，高5dm．如果铁桶装有的水占水桶的(1/4)，那么装的水有多少升？
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3.14 * 4 * 5 * (1/4)</gadget>
<output>15.7</output>

<result>15.7</result>