The height of a triangle remains the same, the base increases by 1.3 cm, and the area increases by 5.2 cm2. If the base remains unchanged, the height increases by 1.5 cm, and the area increases by 9.6 cm2. What is the area of the original triangle?
一个三角形高不变，底增加1.3厘米，面积增加5.2平方厘米，如果底不变，高增加1.5厘米，面积增加9.6平方厘米，原三角形的面积是多少平方厘米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">12.8 * 4</gadget>
<output>51.2</output>

<result>51.2</result>