It should be 121, or +4 or -4 from that. But I am pretty sure it is 121
We notice that the upper trapezoid is symmetric to the lower one & the line of symmetry should be a horizontal line (mirror line) where any point of the upper vertices should be at equal distance (perpendicular) with the related vertices of the lower one from this horizontal line:
Note that QQ" =4 units, Hence the line of symmetry is the perpendicular to QQ' at 2 units
