A piece of iron wire can exactly form a square with a side length of 6 cm. What is the length of this wire in cm?
一根铁丝正好可以围成一个边长6厘米的正方形，这根铁丝长多少厘米．
<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<result>24</result>