The sum of the upper and lower bases of a trapezoid is 32cm, and the height is 9cm. What is the area of the trapezoid?
一个梯形上、下底的和是32cm，高是9cm，这个梯形的面积是多少．
<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">32 * (9/2)</gadget>
<output>144</output>

<result>144</result>