It is known that a:b=c:d, now a is expanded by 3 times, b is reduced to the original (1/3), c remains unchanged, how much should be d, the proportional formula still holds.
已知a：b=c：d，现将a扩大3倍，b缩小到原来的(1/3)，c不变，d应多少，比例式仍然成立．
<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<result>1/9 = around 0.111111</result>