Xiaohong forms an isosceles triangle with a rope of 40 cm (the length of the point where the two ends of the rope collide is ignored), its base is 12 cm long, and how long is one of its waists in cm?
小红用40厘米的绳子围成一个等腰三角形(绳子两端相撞处的长度忽略不计)，它的底边长12厘米，它的一条腰长多少厘米．
<gadget id="calculator">40 - 12</gadget>
<output>28</output>

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

<result>14</result>