The base of a cuboid is a square with an area of 9 square decimeters, and its side is exactly a square. What is the side area of this cuboid?
一个长方体的底是面积为9平方分米的正方形，它的侧而展开图正好是一个正方形，这个长方体的侧面积是多少平方分米．
<gadget id="calculator">9 * 16</gadget>
<output>144</output>

<result>144</result>