rectangle and a square have the same perimeter. The length of the rectangle is 12 cm and the width is 6 cm. What is the side length of the square in cm? (solution by equation)
一个长方形和一个正方形的周长相等，长方形长12厘米，宽6厘米，正方形的边长是多少厘米？(用方程解)
<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">24 + 12</gadget>
<output>36</output>

<gadget id="calculator">36 / 4</gadget>
<output>9</output>

<result>9</result>