Use 30 cm long iron wire to form an isosceles triangle. The ratio of the waist to the base is 2:1. What is the length of the base in cm?
用30厘米长的铁丝围成一个等腰三角形，已知腰和底的比是2：1，底长是多少厘米．
<gadget id="calculator">2 + 2 + 1</gadget>
<output>5</output>

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

<gadget id="calculator">30 * (1/5)</gadget>
<output>6</output>

<result>6</result>