Put a watermelon into a cuboid pool with a length of 4.5 decimeters, a width of 3.8 decimeters, and a height of 3.5 decimeters. After the watermelon is submerged in the water, the water level rises by 0.4 decimeters. What is the volume of the watermelon?
把一个西瓜放入一个长4.5分米，宽3.8分米，高3.5分米的长方体水池中，水面没过西瓜后，水面上升了0.4分米，这个西瓜的体积是多少？
<gadget id="calculator">4.5 * 3.8 * 0.4</gadget>
<output>6.84</output>

<result>6.84</result>