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Lesson Plan #005
Date: Friday September 21st, 2015
Class: Geometry
Topic: Definitions involving perpendicular lines
Aim: What are some definitions involving perpendicular lines?
HW #005:
Page 58 #’s 9-12
Objectives:
1) Students will be able to solve problems involving perpendicular lines
Do Now:
How would you classify perpendicular lines?
PROCEDURE:
Write the Aim and Do Now
Get students working!
Take attendance
Give Back HW
Collect HW
Go over the Do Now
Notation for perpendicular lines
Definition: Perpendicular lines are two lines that intersect to form right angles.
http://www.mathopenref.com/perpendicular.html
Definition: The perpendicular bisector of a line segment is a line, a line
segment or ray that is perpendicular to the line segment and bisects the line
segment.
Definition: The distance from a point to a line is the length of the
perpendicular from the point to the line.
Constructions
To bisect a given line segment (by constructing the perpendicular bisector of a given line segment).
To construct the perpendicular bisector of AB:
1. Draw two circles with the same radius and with centers at the endpoints of segment AB. The
radius must be long enough for the two circles to intersect.
2. Mark the points of intersection P and Q of the two circles.
3. Draw line PQ. This is the perpendicular bisector of segment AB.
4. Mark the intersection M of line PQ with segment AB. This is the midpoint of segment AB.
http://www.mathsisfun.com/geometry/construct-linebisect.html
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Assignment #1:
Construct the perpendicular bisector of
AB
A
B
Assignment #2:
Construct a line segment whose measure is
A
1
2 ( AB )
2
B
Assignment #3:
Construct a
45o angle
A
B
Assignment #4:
How could you locate the midpoint of a line segment via construction?
Assignment #5:
The owners of these two houses would like to put up a fence that runs equidistant between the two homes. Via construction, show
where the fence would lie
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If Enough Time:
1) Suppose you had a segment of length 3 and a segment of length 5. In a few complete sentences, explain
how you would construct a segment of length 8? A segment of length 2?
2)
3)
4) If C is the midpoint of AB and PC  AB , then PC is called a(n) ________________
of AB .
5) a) Construct a Copy of angle YUK
b) Construct the bisector of Angle YUK
c) Find the midpoint of YU via
construction and label it M.