Since it’s a parallelogram, AB is parallel to DC and AD is parallel to BC. So, we can start looking at angle relationships. my drawing is horrible, but I basically drew a corresponding angle (congruent if lines are parallel) to DAB, which is then alternate interior angles with Y (congruent if lines are parallel) so, 145
when multiplying matrixes the number of columns of the first matrix must be equal as the number of rows of the second matrix, and since here matrix A has 4 columns but matrix B has 5 rows they can't be multiplied
