rectangle has a ratio of length to width of 7:3. If the length is reduced by 12 decimeters and the width is increased by 16 decimeters, it becomes a square. What is the area of the original rectangle? (drawing analysis)
一个长方形，长与宽的比是7：3，如果把长减少12分米，宽增加16分米，就变成正方形．原来长方形的面积是多少平方分米？(画图分析)
<gadget id="calculator">12 + 16</gadget>
<output>28</output>

<gadget id="calculator">7 - 3</gadget>
<output>4</output>

<gadget id="calculator">28 / 4</gadget>
<output>7</output>

<gadget id="calculator">7 * 7 * 7 * 3</gadget>
<output>1_029</output>

<result>1_029</result>