In a ratio, the product of two outer terms is 5, one inner term is 0.4, and what is the other inner term.
在一个比例里，两个外项的积是5，一个内项是0.4，另一个内项是多少．
<gadget id="calculator">5 / 0.4</gadget>
<output>12.5</output>

<result>12.5</result>