An isosceles triangle with a base length of 8 decimeters is surrounded by an iron wire with a length of 18 decimeters. What is the length of the waist of this isosceles triangle?
用一根长18分米的铁丝围成一个底边长8分米的等腰三角形，这个等腰三角形的腰长是多少分米？
<gadget id="calculator">18 - 8</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<result>5</result>