The perimeter of an isosceles triangle is 156 cm and the base is 66 cm. What is its waist length in cm?
一个等腰三角形的周长是156厘米，底边长是66厘米，它的腰长是多少厘米？
<gadget id="calculator">156 - 66</gadget>
<output>90</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<result>45</result>