From the information given,
angle 6 = 141
angle 5 = 180 - angle 6(Because they are on a straight line)
angle 5 = 180 - 141 = 39
angle 5 = angle 3(Alternate angles are congruent)
ang;e 3 = 39
angle 4 = 180 - 39(Because they are on a straight line)
angle 4 = 141 degrees