1. CHAPTER 3
SECTION 6

2. Using Perpendicular and Parallel Lines:
Goal: Construct parallel and perpendicular lines.
Use properties of parallel and perpendicular lines.
A construction is a geometric drawing that uses a limited set of tools,
usually a compass and a straightedge.
Parallel Postulate:
Words: if there is a line and a point not on the line, then there
is exactly one line through the point parallel to the given line.
Symbols: if P is not on line l, then there exists one line m through P such that mǁ l.

3. Perpendicular Postulate:
Words: if there is a line and a point not on the line, then
there is exactly one line through the point
perpendicular to the given line.
Symbol: if P is not on line l, then there exists one line
through P such that m l.

4. Theorem 3.11
Words: If two lines are parallel to the same line,
then they are parallel to each other.
Symbols: If q ǁ r and r ǁ s, then q ǁ s. q r s

5. Theorem 3.12
Words: In a plane, if two lines are perpendicular to the same line,
then they are parallel to each other.
Symbols: If m p and n p then m ǁ n. m n p

6. Examples: m
2x + 2 n
Find the value of x that makes m ǁ n.

7. p q
3x + 28 5x
Find the value of x so that p ǁ q.

8. PRACTICE
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1-21,27-32