Cartesian System

When a right handed rectangular cartesian system oxyz is rotated about the z-axis through an angle pi/4 in the counter clockwise direction. It is found that a vector bar(a) has the components 2sqrt(2), 3sqrt(2), 4 . The components of bar(a) in the oxyz coordinate system are

Cartesian plane

What is meant by Cartesian coordinate system?

What is meant by right-handed Cartesian coordinate system ?