A glass fish tank is in the shape of a cube with a side length of 3dm. How many square decimeters of glass are needed to make this fish tank? (There is no cover on the top of the fish tank)
一个玻璃鱼缸的形状是正方体，棱长3dm，制作这个鱼缸至少要玻璃多少平方分米？(鱼缸的上面没有盖)
<gadget id="calculator">3 * 3 * 5</gadget>
<output>45</output>

<result>45</result>