 
Summary: 12.1 ThreDimensional Coordinate Systems
3Dimensional Rectangular Coordinate System
· 3Dimensional Coordinate System
consists three mutually perpendicular coordinate lines, called Xaxis, Yaxis,
Zaxis which intersect at a point called, origin.
· Coordinate Planes
Three planes determined by coordinate axes are called XYplane, XZplane,
YZplane
Yaxis
Xaxis
Zaxis
YZplane
XZplane
XYplane
In XYplane, z=0; In YZplane, x=0; In XZplane, y=0.
x a= is a plane parallel to YZplane and intersecting Xaxis at x a=
y b= is a plane parallel to XZplane and intersecting Yaxis at y b=
z c= is a plane parallel to XYplane and intersecting Zaxis at z c=
· Octants
Coordinate planes divide 3space into 8 parts called octants
