A classroom is 9 meters long and 7.2 meters wide. It is planned to lay square bricks on the floor. How many decimeters of square bricks are selected so that the floor is a whole square brick.
一间教室长9米，宽7.2米，计划在地面上铺方砖，选边长多少分米的方砖能使地面都是整块方砖．
<result>6</result>