Angle four is 30° and angle 7 is 150! angle four equals 30° because a straight line equals 180, and 180-150=30. angle 7 is 150 through corresponding angles
the exterior angle at angle C, and angle C, are supplementary. since angle C is 51 because of the interior angle triangle sum theorem, then the exterior angle is: 180 -51 = 129 degrees.