The lower base of an isosceles trapezoid is 8 cm, which is 4 times the upper base, and its circumference is 22 cm. What is the waist of this isosceles trapezoid in cm? ．
一个等腰梯形的下底是8厘米，是上底的4倍，它的周长是22厘米，这个等腰梯形的腰是多少厘米？．
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">22 - 8 - 2</gadget>
<output>12</output>

<gadget id="calculator">12 / 2</gadget>
<output>6</output>

<result>6</result>