In the ratio, the product of two outer terms is 1, one inner term is (5/7) and the other inner term is known.
在比例中，两个外项的乘积是1，已知一个内项是(5/7)，另一个内项是多少．
<gadget id="calculator">7 / 5</gadget>
<output>7/5 = around 1.4</output>

<result>7/5 = around 1.4</result>