If a rectangle is 7 cm long and 5 cm wide, what is the side length of a square equal to its perimeter?
一个长方形长7厘米，宽5厘米，与它周长相等的正方形的边长是多少厘米．
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">12 * 2</gadget>
<output>24</output>

<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<result>6</result>