Geometry involves points and sets of points called
lines, planes, and surfaces.
Geometry can be separated into two
1. Traditional (which is the geometry of Euclid)
2. Transformational (which is more algebraic than the
When Euclid was formalizing traditional
geometry, he based it on the following five postulates:
1. A straight line can be drawn from any point
to any other point.
2. A straight line extends infinitely far in either
3. A circle can be described with any point as center
and with a radius equal to any
finite straight line drawn from the center.
4. All right angles are equal to each other.
5. Given a straight line and any point not on this line,
there is one and only one line
through that point that is parallel
to the given line.