If the perimeter of an isosceles triangle is 40cm and the length of the base is 12cm, what is the length of one of the sides in cm?
等腰三角形的周长是40cm，底边的长是12cm，则其中一条腰的长是多少cm．
<gadget id="calculator">40 - 12</gadget>
<output>28</output>

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

<result>14</result>