If ABDE and CDFG are parallelograms, you could do it like this:
1) ABDE and CDFG are parallelograms. (given)
2) Angle A is congruent to Angle D. (opposite angels of a parallelogram are congruent)
3) Angel D is congruent to Angle G. (same as 2)
4) Angel A is congruent to Angle G. (If two angles are congruent to the same angle, they are congruent)