The radius of the base of a cylinder is 3cm and the height is 12cm. What is its volume in cm**3.
一个圆柱的底面半径是3cm，高是12cm，它的体积是多少cm**3．
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 12</gadget>
<output>339.12</output>

<result>339.12</result>