Mom puts some potatoes in a cylindrical container with a bottom area of 40 square centimeters to wash. At this time, the water depth in the container is 30 cm; after taking out the potatoes, the water level drops by 3 cm. What is the volume of these potatoes in cubic centimeters?
妈妈把一些土豆放在底面积是40平方厘米的圆柱形状的容器里清洗，这时容器里的水深30厘米；拿出土豆后，水面下降了3厘米．这些土豆的体积是多少立方厘米．
<gadget id="calculator">40 * 3</gadget>
<output>120</output>

<result>120</result>