A piece of parallelogram steel plate, with an area of 378 decimeters square, can just fit in an iron frame with a bottom of 21 decimeters. How many decimeters should the height of the iron frame be?
一块平行四边形的钢板，面积是378平方分米，正好能放在一个底是21分米的铁框中，铁框的高应是多少分米？
<gadget id="calculator">378 / 21</gadget>
<output>18</output>

<result>18</result>