Download Geometry Section 3.1 - West End Public Schools

Geometry
Section 3.1
Identify Pairs of Lines and
Angles
Postulates
1.
2.
3.
Through any two points there exists
exactly one line
A line contains at least two points
If two lines intersect, then their
intersection is exactly one point.
Postulates
1.
2.
3.
4.
Through any three noncollinear points
there exists exactly one plane.
A plane contains at least three
noncollinear points
If two points lie in a plane, then the line
containing them lies in the plane.
If two planes intersect, then their
intersection is a line.
Angle Theorems and Postulates

Right angles congruence theorem


Linear Pair Postulate


All right angles are congruent
If two angles form a linear pair, then they are
supplementary
Vertical Angles Congruence Theorem

Vertical angles are congruent

Two coplaner lines that do not intersect
are called parallel lines

Two lines are skew lines if they do not
intersect and are not coplaner

Two planes that do not intersect are
parallel planes
Line Postulates

Parallel postulate


If there is a line and a point not on the line,
there is exactly one line through that point
that is parallel to the given line.
Perpendicular postulate

If there is a line and a point not on the line,
there is exactly one line through that point
that is perpendicular to the given line.
Angles formed by Transversals
A transversal is a line that intersects two
ore more coplaner lines at different points.
 Corresponding angles have
corresponding positions

1
2

Alternate interior angles are between
the two lines, and on opposite sides of the
transversal
3
4

Alternate exterior angles lie outside the
two lines and on opposite sides of the
transversal
5
6

Consecutive interior angles lie between
the two lines on the same side of the
transversal
7
8
Name the Angles!!
2
3
1
4
5
6
7
8
Assignment
Section 3.1
 Page 150
 Problems # 4-10 even, 11-14, 18-23, 2432, 40-42
