A 40 cm wire is used to form an isosceles trapezoid with a waist of 6 cm and a height of 8 cm. What is the area?
用一根40厘米的铁丝围成一等腰梯形，腰是6厘米，高为8厘米，面积是多少．
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">40 - 12</gadget>
<output>28</output>

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

<gadget id="calculator">28 * 4</gadget>
<output>112</output>

<result>112</result>