A trapezoid has an upper base of 12m, a lower base of 28m, and a height of 8m. What is the area?
一个梯形，上底12m，下底28m，高8m，面积是多少？
<gadget id="calculator">12 + 28</gadget>
<output>40</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">40 * 4</gadget>
<output>160</output>

<result>160</result>