this is a parallelogram. so, that means that adjacent angles are equal. that means that angle B is equal to angle D. that means that we can label angle B as 75 degrees. and, we know that a square is 360 degrees. so, if we take the 150 degrees of angle B and angle D combined, then we have 210 degrees to work with. but, since it is a parallelogram, we can divide 210 in half and get both angles. so, each angle is 105 degrees. and that is how we got the answer.
