The measures of the exterior angles at three vertices of some quadrilaterals are given. Find the measure of the exterior angle at the fourth vertex.
a) 75°, 125°, 35° b) 50°, 145°, 85° c) 76°, 34°, 178° d) 93°, 83°, 121°
a) 75°, 125°, 35° b) 50°, 145°, 85° c) 76°, 34°, 178° d) 93°, 83°, 121°