The cross section of a canal is trapezoidal, the width of the mouth is 4.8 meters, the width of the bottom is 2.2 meters, and the depth of the canal is 0.8 meters. What is the area of the cross section in square meters?
一条水渠的横截面是梯形，渠口宽4.8米，渠底宽2.2米，渠深0.8米，横截面的面积是多少平方米．
<gadget id="calculator">2.2 + 4.8</gadget>
<output>7</output>

<gadget id="calculator">0.8 / 2</gadget>
<output>0.4</output>

<gadget id="calculator">7 * 0.4</gadget>
<output>2.8</output>

<result>2.8</result>