A trapezoidal flower bed is 12 meters high and the sum of the upper and lower bases is 20 meters. What is the area in square meters?
一个近似梯形的花坛，高12米，上下底之和是20米，面积是多少平方米．
<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">20 * 6</gadget>
<output>120</output>

<result>120</result>