There is a parallelogram iron plate with a base of 8dm and a height of 3.5dm. The average weight of this iron plate is 0.75kg per square decimeter. How many kilograms does this iron plate weigh?
有一块平行四边形的铁板，底是8dm，高是3.5dm，这块铁板平均每平方分米重0.75kg，这块铁板重多少千克？
<gadget id="calculator">8 * 3.5 * 0.75</gadget>
<output>21</output>

<result>21</result>