Use a steel bar with a length of 48 cm to weld it into a cuboid model, and its bottom surface is a square with a side length of 3 cm. Paste white paper on the outside of this model, at least how many square centimeters of white paper should be used?
用一根长48cm的钢筋，焊成一个长方体模型，它的底面为边长3cm的正方形．在这个模型的外面糊上白纸，至少要用多少平方厘米的白纸？
<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">48 / 4</gadget>
<output>12</output>

<gadget id="calculator">3 + 3</gadget>
<output>6</output>

<gadget id="calculator">12 - 6</gadget>
<output>6</output>

<gadget id="calculator">3 * 6</gadget>
<output>18</output>

<gadget id="calculator">9 + 18 + 18</gadget>
<output>45</output>

<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<result>90</result>