The base of a triangle is 9 decimeters long. If the base is extended by 3 decimeters, the area will increase by 12 decimeters. What is the area of the triangle?
一个三角形的底长9分米，如果底边延长3分米，面积就增加12平方分米，原来这个三角形的面积是多少平方分米．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">12 * (2/3)</gadget>
<output>8</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>