Answer-
The value of y is 6 units.
Solution-
Given ∆ABC ≅ ∆GEF
If two triangles are congruent, then the corresponding sides are also congruent.
So,
EF = BC, GF = AC
Putting the values,
--------------1

--------------------2
Putting the values of x in equation 1,


Therefore, the value of y is 6 units.