The perimeter of an isosceles triangle is 60 cm and the length of one side is 18 cm. What is its base length in centimeters?
一个等腰三角形的周长是60厘米，一条腰的长度是18厘米．它的底长是多少厘米？
<gadget id="calculator">18 * 2</gadget>
<output>36</output>

<gadget id="calculator">60 - 36</gadget>
<output>24</output>

<result>24</result>