The top of a trapezoid is 2 decimeters, the bottom is 6 decimeters, and the height is 3.5 decimeters. What is its area in square decimeters?
一个梯形的上是2分米，下底是6分米，高是3.5分米，它的面积是多少平方分米．
<gadget id="calculator">2 + 6</gadget>
<output>8</output>

<gadget id="calculator">3.5 / 2</gadget>
<output>1.75</output>

<gadget id="calculator">8 * 1.75</gadget>
<output>14</output>

<result>14</result>