stone is placed in a cylindrical water cup with a bottom area of 30 square centimeters, and the water level rises by 4 centimeters, what is the volume of the stone?
再一个底面积为30平方厘米的圆柱形水杯中放入一块石头，水面比原来升高了4厘米，石头的体积是多少．
<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>