A newly dug canal has a trapezoidal cross-section. The mouth of the canal is 2.8 meters wide, the bottom of the canal is 1.4 meters wide, and the canal is 1.2 meters deep. What is its cross-sectional area in square meters?
一条新挖的水渠，横截面是梯形．渠口宽2.8米渠底宽1.4米，渠深1.2米．它的横截面的面积是多少平方米？
<gadget id="calculator">1.4 + 2.8</gadget>
<output>4.2</output>

<gadget id="calculator">1.2 / 2</gadget>
<output>0.6</output>

<gadget id="calculator">4.2 * 0.6</gadget>
<output>2.52</output>

<result>2.52</result>