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Chapter 3.1 Identify Pairs of Lines and Angles

M11.B.2.1, M11.C.1.2

- What angle pairs are formed by transversals?

- Parallel lines
- never intersect
- are coplanar
- The symbol for parallel lines is
- If line l is parallel to line m you can represent

it with l m . - When 2 drawn lines are parallel there will be

little arrows or triangles on the lines.

Are these parallel judging by sight?

R

Are these parallel?

S

Are these parallel?

Are these parallel?

y

z

Parallel Planes

- Parallel planes are two planes that do not

intersect.

Perpendicular Planes

- Perpendicular Planes are planes that intersect at

a 90 angle.

Skewed Lines

- Skewed lines do not intersect, but are not

coplanar. - The last 2 examples were examples of skewed lines.

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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.

.

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.

.

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- 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