A cylindrical wooden barrel, the inner diameter of the bottom surface is 4dm, the minimum height of the mouth of the barrel from the bottom surface is 5dm, and the maximum height is 7dm. How much water can the bucket hold?
一个圆柱形木桶，底面内直径为4dm，桶口距底面最小高度为5dm，最大高度为7dm．该桶最多能装多少水．
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">3.14 * 4 * 5</gadget>
<output>62.8</output>

<result>62.8</result>