A thin iron wire with a length of 40 cm is folded into an isosceles triangle with a base length of 12 cm. What is the length of one of its waists in cm?
把一根长为40cm的细铁丝折成一个底边长12cm的等腰三角形，它的一条腰的长是多少厘米．
<gadget id="calculator">40 - 12</gadget>
<output>28</output>

<gadget id="calculator">28 / 2</gadget>
<output>14</output>

<result>14</result>