A cylinder has a base radius of 4m and a height of 7m. If the height remains the same and the radius of the base is doubled, the volume will increase by how many times
一个圆柱的底面半径为4m，高为7m，如果高不变，底面半径扩大2倍，体积就扩大多少倍
<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<result>4</result>