Chapter 3 – Perpendicular and Parallel Lines
The Bigger Picture
-Properties of Perpendicular and Parallel Lines
-How to Write a Flow Proof – Valuable Logic for Project
Related Planning
-Foundational Skills for solving problems with triangles, and
practical applications such as carpentry,
engineering, & physics
The “What” and the “Why”
Identify relationships between Lines
Prove that Lines are Parallel
Identify angles formed by coplanar
lines intersected by a transversal
Use properties of parallel lines
- Scientific applications such as paths of light, reflection,
-Laying the foundation for work with angles and
their proofs
Prove and use results about
perpendicular lines
-Useful application for real-life situations such
as carpentry and construction related analysis
Write Flow Proofs
-Learn the basics of flow diagrams in support of
proofs. Valuable real-life tool used for project
planning in virtually every industry
Prove and use results about parallel
lines and transversals
- Understand the world around you with regard
to intersecting lines and the angles they form
and refraction
Use Slope in a coordinate plane to determine if
lines are parallel
- Introduction to the concepts of coordinate geometry
Write an equation of a line parallel to a given
line in a coordinate plane
- Foundation for writing coordinate proofs
Use Slope to decide if lines in a coordinate
plane are perpendicular
-Solving real life problems regarding the determining of
right angle formations
Write an equation of a line perpendicular to a
given line.
Perpendicular and Parallel Lines
Sailboats are actually designed to sail
against the wind. Most sailboats
can sail at an angle of 45* to the
direction from which the wind is
blowing. If a sailboat heads
directly into the wind, the sail
simply flaps and becomes
useless.
1
45*
45*
Wind
In the drawing to the right, what do
you think the measure of angle 1
is based on the path in which both
boats are traveling?
If the boats always sail at a 45* angle
to the wind, and the wind doesn’t
change direction, do you think the
boats paths will ever cross?
Wind