Given dimensions of the photograph is:
Length = 6 inches
Width = 4 inches.
Ratio of original length and width
Length : Width = 6 : 4 <=> 3.2
After enlarging the photograph, width becomes 16 inches.
It means the width of the original photograph is multiplied with 4.
Similarly, the length is also multiplied by 4
Ratio of new dimensions
Length :Width = 24 : 16 < = > 3:2
The ratio of dimensions of the original and enlarged photographs are same.
Hence, the new length is 24 inch