An isosceles triangle is surrounded by a thin iron wire with a length of 30 cm. If the base of the formed triangle is 8 cm long, how long is its waist in cm?
用1根长30厘米的细铁丝围成一个等腰三角形，如果围成的三角形的底边长8厘米，那它的一条腰长多少厘米？
<gadget id="calculator">30 - 8</gadget>
<output>22</output>

<gadget id="calculator">22 / 2</gadget>
<output>11</output>

<result>11</result>