The height of a parallelogram is 6.5 decimeters. If the base remains unchanged and the height decreases by 3 decimeters, the area decreases by 12 square decimeters. What is the original area of the parallelogram?
一个平行四边行高为6.5分米，若底不变，高减少3分米，面积就减少12平方分米，那么原来平行四边行的面积是多少平方分米．
<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 6.5</gadget>
<output>26</output>

<result>26</result>