SOLUTION: What is the missing number in the proportion 4 : n = 3 : 9

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Question 742432: What is the missing number in the proportion 4 : n = 3 : 9
Answer by jim_thompson5910(35256) About Me  (Show Source):
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4 : n = 3 : 9

4/n = 3/9

4*9 = 3n

36 = 3n

36/3 = n

12 = n

n = 12