The upper base of a trapezoid is 15 meters, the lower base is 25 meters, and the height is 9 meters. What is its area m**2.
一个梯形上底是15米，下底是25米，高是9米，它的面积是多少m**2．
<gadget id="calculator">15 + 25</gadget>
<output>40</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">40 * (9/2)</gadget>
<output>180</output>

<result>180</result>