The missing values of the congruent shapes are:
y = 4
x = 17.5
How to find the lengths of the congruent shapes?
We are told that the quadrilaterals are congruent. Thus:
ABCD ≅ FGCD
This means corresponding angles and sides are congruent by the CPCTC Postulate.
Thus:
AB ≅ FG
3y + 2 = 14
3y = 12
y = 4
Similarly:
4x + 21 = 91
4x = 70
x = 70/4
x = 17.5