The perimeter of an isosceles triangle is 36 cm. Given that the ratio of the two sides is 2:5, what is the length of its base in centimeters?
一个等腰三角形的周长是36厘米．已知两条边的比是2：5，它的底边长是多少厘米？
<gadget id="calculator">2 + 5 + 5</gadget>
<output>12</output>

<gadget id="calculator">2 / 12</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">36 * (1/6)</gadget>
<output>6</output>

<result>6</result>