A marksman fires a practice round from A toward a target B. If the target diameter is 160 mm and the target center is at the same altitude as the

end of the rifle barrel, determine the"shallow" launch angles 0 for which the round will strike the target. Neglect aerodynamic drag and assume that the round is directed along the vertical centerline of the target. (Note: The word"shallow" indicates a low-flying trajectory for the round.)