The ratio of 7 to 9 is equal to the ratio of 49 to x.
7与9的比等于49与x的比．
<gadget id="calculator">7 / 9</gadget>
<output>7/9 = around 0.777778</output>

<gadget id="calculator">49 / (7/9)</gadget>
<output>63</output>

<result>63</result>