Two perfectly equal trapezoids, the upper base is 15 cm long, the lower base is 24 cm long, and the height is 12 cm. If these two trapezoids are put together to form a parallelogram, what is the area of the parallelogram?
两个完全相等的梯形，上底长15cm，下底长24cm，高12cm．如果把这两个梯形拼成一个平行四边形，这个平行四边形的面积是多少？
<gadget id="calculator">15 + 24</gadget>
<output>39</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<gadget id="calculator">39 * 6 * 2</gadget>
<output>468</output>

<result>468</result>