A, because
rectangle- at least 1 angle should be 90 degrees.
square- all angles and sides should have the same measures.
quadrilateral- its any shape with 4 sides.
parallelogram-both pairs of opposite sides parallel and congruent.
rhombus-diagonals are perpendicular which means the angle of the perpendicular lines would be 90 degrees.
So x equals 30 because u did 180-150 and y is also 30 since you found x you then add 90 plus 30 and it will give u 120 then 180 minus 120 will be 60 then 90 - 60 because u are trying to find y, and u will get 30.
It is 0 because anything multiplied by 0 is 0.