If the sum of the sides of a cube is 84 cm, what is its surface area in square centimeters?
一个正方体的棱长总和是84厘米，它的表面积是多少平方厘米．
<gadget id="calculator">84 / 12</gadget>
<output>7</output>

<gadget id="calculator">7 * 7 * 6</gadget>
<output>294</output>

<result>294</result>