Is the ratio 25 to 16 proportional to the ratio 5 to 4

To check you can set the ratios up as fractions, then cross multiply.  

If they equal the same thing they are proportional, if they don't, they are not.
   25  =  5
   16      4

Cross multiply (25)(4) = (16)(5)
                          100 = 80

Since 100 does NOT equal 80 the ratios are NOT proportional. 

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