The base of a triangle is 3m long. If the base is extended by 1m, the area of the triangle increases by 1.2 square meters. What is the area of the original triangle in square meters?
一个三角的底长3m，如果底延长1m，那么三角形的面积就增加1.2平方米．原来三角形的面积是多少平方米．
<gadget id="calculator">2 / 1</gadget>
<output>2</output>

<gadget id="calculator">1.2 * 2</gadget>
<output>2.4</output>

<gadget id="calculator">2.4 / 2</gadget>
<output>1.2</output>

<gadget id="calculator">3 * 1.2</gadget>
<output>3.6</output>

<result>3.6</result>