A unit wants to build a cuboid pool with a required depth of 4 meters and a perimeter of 120 meters at the bottom of the pool. How to design the pool to have the largest volume? What is the maximum?
某单位要建一个长方体水池，要求深度为4米，水池底面的周长为120米，怎样设计水池的容积最大？最大是多少？
<gadget id="calculator">120 / 4</gadget>
<output>30</output>

<gadget id="calculator">30 * 30 * 4</gadget>
<output>3_600</output>

<result>3_600</result>