A 1.8-meter-long cuboid steel is cut into three sections, and the surface area increases by 7.2 square decimeters compared to the original one. What is the original volume of the steel in cubic decimeters?
一个长1.8米的长方体钢材截成三段，表面积比原来增加7.2平方分米，这根钢材原来的体积是多少立方分米．
<gadget id="calculator">7.2 / 4</gadget>
<output>1.8</output>

<gadget id="calculator">1.8 * 1.8</gadget>
<output>3.24</output>

<gadget id="calculator">3.24 * 10</gadget>
<output>32.4</output>

<result>32.4</result>