In a ratio, the product of two inner terms is 2, one outer term is 13, and the other outer term is what.
在一个比例里，两个内项的积为2，一个外项是13，另外一个外项是多少．
<gadget id="calculator">2 / 13</gadget>
<output>2/13 = around 0.153846</output>

<result>2/13 = around 0.153846</result>