Since the evidence presented at trial upholds the state's assertion that defendant fired his weapon at the victim while the victim, unarmed, was in the act of walking away from the defendant, the jury was authorized to reject defendant's contentions of self-defense (see Smith v. State, 232 Ga. 99 (2) ( 205 S.E.2d 188); Giles v. State, 239 Ga. 835 ( 239 S.E.2d 25)) and find defendant guilty of the offense charged. See, e.g., Smith v. State, 142 Ga. App. 82 ( 235 S.E.2d 44); Tucker v. State, 144 Ga. App. 30 (1) ( 240 S.E.2d 304); Hendrix v. State, 145 Ga. App. 170 (1) ( 243 S.E.2d 112). A review of the record thus reveals that a rational trier of fact could reasonably have found defendant guilty of aggravated assault beyond a reasonable doubt.