Easy
If 15:x :: 18:12, find the value of x.
Explanation
Explanation
In a proportion a:b :: c:d, we have a/b = c/d. So 15/x = 18/12, which gives x = (15 x 12)/18 = 180/18 = 10.
PRO TIP
Re-check your working by substituting the answer back into the original question.