Download Chapter 3.1: Identify Pairs of Lines and Angles

Chapter 3.1: Identify
Pairs of Lines and Angles

What angle pairs are formed by
transversals?
M11.B.2.1, M11.C.1.2

Parallel lines
◦ never intersect
◦ are coplanar
◦ The symbol for parallel lines is ||
◦ If line
l
l is parallel to line m you can represent it with
||
m.
◦ When 2 drawn lines are parallel there will be little arrows
or triangles on the lines.
Are these parallel judging by
sight?
Are these parallel?
Are these parallel?
Are these parallel?

Parallel planes are two planes that do not
intersect.
Parallel Planes

Perpendicular Planes are planes that
intersect at a 90˚ angle.
Perpendicular Planes

Skewed lines do not intersect, but are not
coplanar.

The last 2 examples were examples of
skewed lines.
Skewed Lines
Parallel Postulate

If there is a line and a point not on that
line, then you can draw only 1 line parallel
to the line that passes through that point.
Not parallel
.
Perpendicular Postulate

If there is a line and a point, then there is
one line that passes through the point
that is perpendicular to the line.
.
Not
Perpendicular

Page 150

# 3-10
Transversals

Transversals are lines that intersect two or
more coplanar lines at different points.

In other words a line that intersects 2
other lines.
transversal
There are 4 different angle
relationships created by a transversal

Corresponding angles: same side of
transversal and of the individual lines.
(angles 2 and 6)

Alternate interior: angles on the inside of
the 2 lines, but on either side of the
transversal. (angles 4 and 5)

Alternate exterior: angles on the outside
of the lines, but on opposite sides of the
transversal. (angles 1 and 8)

Consecutive interior: angles on the inside
of the lines and on the same side of the
transversal. (angles 3 and 5)
Identify Angles
1 5
2 6
3
4
7
8