Can angle measurements be negative

Answer 1

Yes, although it may seem strange.

Conventionally, on a Cartesian plane, angles are measured in an anticlockwise dirction, from the x-axis. Consequently, an angle in the clockwise direction could be considered a negative angle. It might be simpler to think of an angle of 359 degrees as one of -1 degrees, instead.

Sometimes you need to subtract one angle from another and in that context, a negative measure for the angle is implicit.