If the base of a parallelogram increases by 1.5 decimeters and the height remains unchanged, the area increases by 9 square decimeters; if the base remains unchanged and the height increases by 1.2 decimeters, the area increases by 4.8 square decimeters. What is the area of the original parallelogram?
一个平行四边形底增加1.5分米，高不变，面积就增加9平方分米；如果底不变，高增加1.2分米，面积就增加4.8平方分米．原来平行四边形的面积是多少．
<gadget id="calculator">4.8 / 1.2</gadget>
<output>4</output>

<gadget id="calculator">9 / 1.5</gadget>
<output>6</output>

<gadget id="calculator">4 * 6</gadget>
<output>24</output>

<result>24</result>