Geometry resources
Teach Yourself (2)

In this unit we find the equation of a straight line, when we are given some
information about the line. The information could be the value of its gradient,
together with the co-ordinates of a point on the line. Alternatively, the
information might be the co-ordinates of two different points on the line.
There are several different ways of expressing the final equation, and some
are more general than others.

In this unit we use a system of co-ordinates to find various properties
of the straight line between two points. We find the distance between the two
points and the mid-point of the line joining the two points.