The areas of the two adjacent faces of the cuboid are 20dm**2 and 12dm**2, and the common edge length of the two adjacent faces is 4dm. Find the surface area of the cuboid.
长方体相邻两个面的面积是20dm**2和12dm**2，相邻两个面的公共棱长是4dm，求长方体的表面积．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<gadget id="calculator">15 + 20 + 12</gadget>
<output>47</output>

<gadget id="calculator">47 * 2</gadget>
<output>94</output>

<result>94</result>