A cylindrical tin bucket without a lid has a base radius of 2 decimeters and a height of 4.5 decimeters measured from the inside. What is the volume of this barrel?
一个无盖的圆柱形铁皮水桶，从里面量底面半径是2分米，高是4.5分米．这个木桶的容积是多少？
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">3.14 * 4 * 4.5</gadget>
<output>56.52</output>

<result>56.52</result>