The rectangular coordinate system is the basis for how we find locations on a map, for example (even though the earth is actually a sphere, this was a basis). I would say it is rather important.
x, y, and z ordinates from origin 0, x and y are two dimensional ordinates ie graph axis, z adds third dimension.eg ordinates for point are say 10, 25, 15: start at 0, right for 10(x), left for...