The sum of a group of adjacent sides of a parallelogram is 50cm, and the two heights are 10cm and 15cm respectively, find the area of this parallelogram.
一个平行四边形的一组邻边之和是50cm，两种高分别是10cm和15cm，求这个平行四边形的面积．
<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<result>300</result>