If a=6, b=10, and b is the middle item in the ratio of a to c, then c=how much.
如果a=6，b=10，b是a与c的比例中项，那么c=多少．
<gadget id="calculator">50 / 3</gadget>
<output>50/3 = around 16.666667</output>

<result>50/3 = around 16.666667</result>