Answer:
18 inches
Explanation:
We have that,
Length of the photo,
= 6 inches and Width of the photo,
= 4 inches.
Now, the photo is enlarged with the new width i.e.
is 12 inches.
Let, the length of the enlarged photo i.e.
be x inches.
Since, the ratio between length and width remains same, we have the relation,

i.e.

i.e.

i.e.

i.e.

i.e.

Hence, the length of enlarged photo is 18 inches.