In a ratio, the product of two outer terms is 4, one of the inner terms is (1/7), and what is the other inner term.
在一个比例中，两个外项的积是4，其中一个内项是(1/7)，另一个内项是多少．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">4 / (1/7)</gadget>
<output>28</output>

<result>28</result>