Build a cylindrical cistern with a depth of 3 meters and a diameter of 4 meters at the bottom. How much water can this cistern store in cubic meters?
修一个深3米，底面直径4米的圆柱形蓄水池，这个蓄水池能蓄多少水多少立方米
<gadget id="calculator">4 / 2</gadget>
<output>2</output>

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

<gadget id="calculator">3.14 * 4 * 3</gadget>
<output>37.68</output>

<result>37.68</result>