The perimeter of an isosceles triangle is 110 centimeters, and one of its sides is 45 centimeters long. What is the length of its base in centimeters?
等腰三角形的周长是110厘米，它的一条腰长45厘米，那么它的底边长是多少厘米？
<gadget id="calculator">45 * 2</gadget>
<output>90</output>

<gadget id="calculator">110 - 90</gadget>
<output>20</output>

<result>20</result>