a:b=b:c, and the ratio of both ratios is 2. How many times a is c.
a：b=b：c，且两个比的比值都是2．a是c的多少倍．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / (1/2)</gadget>
<output>4</output>

<result>4</result>