The area of a trapezoid is 42 square meters. The sum of its upper and lower bases is equal to the base of a parallelogram, and its height is equal to the height of the parallelogram. What is the area of this parallelogram in square meters?
一个梯形的面积是42平方米，它的上下底之和与一个平行四边形的底边相等，高与平行四边形的高相等，这个平行四边形的面积是多少平方米．
<gadget id="calculator">42 * 2</gadget>
<output>84</output>

<result>84</result>