The volume of a cylinder is 30 cubic centimeters. If the height remains the same, the radius of the base is doubled. What is the volume of the cylinder obtained?
一个圆柱的体积是30立方厘米，如果高不变，把它的底面半径扩大到原来的2倍，得到的圆柱的体积是多少立方厘米．
<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>