A rectangular parallelepiped carton with a square bottom, if its sides are unfolded to form a square with a side length of 6 decimeters, how much cardboard is needed to make this carton?
一个底面是正方形的长方体纸盒，将它的侧面展开正好是一个边长为6分米的正方形，做这个纸盒至少要多少纸板？
<gadget id="calculator">6 / 4</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">(3/2) * (3/2) * 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<gadget id="calculator">(9/2) + 36</gadget>
<output>81/2 = around 40.5</output>

<result>81/2 = around 40.5</result>