The perimeter of an isosceles triangle is 60 cm, and the ratio of the two adjacent sides is 1:2. What is the base of this isosceles triangle?
一个等腰三角形周长是60厘米，两条邻边之比为1：2，这个等腰三角形的底是多少厘米？
<gadget id="calculator">2 / 1 / 2</gadget>
<output>1</output>

<gadget id="calculator">1 + 2 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 1 / 2 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">60 * (1/5)</gadget>
<output>12</output>

<result>12</result>