Unit One Lesson One Notes
Unit One Lesson One introduced us to the three basic parts of Euclidian geometry: Points, lines, and planes. Points name a location. They have no size and are represented by a dot. Their notation is usually a lowercase letter. Lines are straight and extend forever, and contain an infinite number of points. They are notated with a script lowercase letter or with two points on the line. Planes are flat surfaces that extend forever in all directions. They are usually notated with three noncollinear points within the plane or with an uppercase script letter. Points, lines, and planes are said to be "undefined terms", which means that they are concepts rather than concrete objects.
Lesson one also introduced us to some postulates. Postulates (or axioms) are statements that are inferred to be true without any actual evidence. These are the postulates we learned about in lesson one.
Lesson one also introduced us to some postulates. Postulates (or axioms) are statements that are inferred to be true without any actual evidence. These are the postulates we learned about in lesson one.
- Through any two points there is exactly one line.
- Through any three noncollinear points there is exactly one plane.
- If two points lie in a plane, then the line containing them also lies in the plane.
- If two unique lines intersect, there intersect at exactly one point.
- If two unique planes intersect, they intersect at exactly one line.