parallelogram, the lengths of two adjacent sides are 4 cm and 8 cm respectively, and the height of one side is 5 cm, what is the area of this parallelogram in square centimeters?
一个平行四边形，两条邻边的长分别是4厘米和8厘米，其中一边上的高为5厘米，这个平行四边形的面积是多少平方厘米．
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>