well in a parallelogram two pairs of angles are congruent so lets say for this one <A and <C are congruent and <B and <D are congruent. The interior angles in a parallelogram always equals 360. so now you have two angle measurements, 24 and 24. so add that 24+24=48 now subtract 360-48= 312. since there are two angles that equal the same amount left you divide 312 by 2 and you have your answer so 312 divided by 2= 156 is the measurement for B and D. hope this helped you have an amazing day.