The upper base of a trapezoid is 3cm, the lower base is 5cm, and the height is 2.6cm. What is the area of the trapezoid in cm**2.
一个梯形的上底是3cm，下底是5cm，高是2.6cm，这个梯形的面积是多少cm**2．
<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">2.6 / 2</gadget>
<output>1.3</output>

<gadget id="calculator">8 * 1.3</gadget>
<output>10.4</output>

<result>10.4</result>