The perimeter of an isosceles triangle is 65 cm, the length of the waist is 20 cm, what is the length of the base in cm?
一个等腰三角形的周长是65厘米，腰长20厘米，底长是多少厘米．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">65 - 40</gadget>
<output>25</output>

<result>25</result>