To find the value of y, we can set up a proportion:

(3 3/4) / (1 1/8) = (2 1/2) / y

First, convert all the mixed numbers to improper fractions:

(15/4) / (9/8) = (5/2) / y

Next, multiply both sides by y to solve for y:

(15/4)(8/9) = 5/2

(2)(5) = 9y

10 = 9y

Finally, divide both sides by 9 to solve for y:

y = 10/9

Therefore, the value of y is 10/9.