These are called coordinates.
Why are two numbers necessary to locate points on a coordinate plane?
It is the straight line equation that can be used to locate coordinates of x and y on the Cartesian plane
You do not have 3 coordinates in the Cartesian plane. The Cartesian plane is a plane and is therefore 2 dimensional. In 2 dimensional space you require only 2 coordinates. 3 coordinates are required to locate a point in 3-dimensional space but then it cannot be a Cartesian PLANE.
You use coordinate grids to locate where things are. You also use them to make any kind of a picture.
you cant really use any direction to locate the stars
Its coordinates, possibly!
Using Lat/Long coordinates.
to locate coordinates ..
These are called coordinates.
I assume you are referring to the "observational shadow" of the Galactic plane.Then there are no coordinates
Polar coodinates
The coordinates 12°N 86°W locate the city of Managua, the capital of Nicaragua.
They are the x and y coordinates.
Why are two numbers necessary to locate points on a coordinate plane?
You can locate a point by associating it to coordinates, either in a two dimension plan, x, y, or three dimensional, x, y, z.
It is the straight line equation that can be used to locate coordinates of x and y on the Cartesian plane