The height of a trapezoidal garden is 1.2m, and the sum of the upper and lower bases is 2.4m. If the upper base is extended by 0.4m, it becomes a parallelogram. What is the base of this parallelogram?
一个梯形花圃高是1.2m，上、下底的和是2.4m，如果把上底延长0.4m后就变成一个平行四边形，这个平行四边形花圃的底是多少．
<gadget id="calculator">2.4 + 0.4</gadget>
<output>2.8</output>

<gadget id="calculator">2.8 / 2</gadget>
<output>1.4</output>

<result>1.4</result>