The sum of the upper and lower bases of a trapezoid is 8 meters and the height is 3 meters. What is the area of the trapezoid in square meters?
一个梯形的上下底之和是8米，高是3米，这个梯形的面积是多少平方米．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">8 * (3/2)</gadget>
<output>12</output>

<result>12</result>