Coordinate Axes and Coordinate Planes in Three Dimensional Space
Consider three planes intersecting at a point O such that these three planes are mutually perpendicular to each other . These three planes intersect along the lines X , Y & Z , called the x , y and z-axes , respectively . We may note that these lines are mutually perpendicular to each other . These lines constitute the rectangular coordinate system . The planes XOY , YOZ and ZOX , called , respectively the XY-plane , YZ-plane and the ZXplane , are known as the three coordinate planes . The point O is called the origin of the coordinate system . The three coordinate planes . These three coordinate planes divide the space into eight parts known as octants .
Note : By convention , we take the XOY plane as the plane of the paper and the line Z ′ OZ as perpendicular to the plane XOY .