The sum of the upper and lower bases of the trapezoid is 30 meters, and the height is 8 meters. What is the area of the trapezoid in square meters?
梯形上下底的和是30米，高是8米，梯形的面积是多少平方米．
<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>