Download Do Now

DO NOW
• Take a ruler from the bookshelf.
• Have your syllabus contract out and ready to turn
in.
• Take out your notebook for this class.
• In your notebook, describe the two types of
symmetry and draw an example of each.
BUILDING BLOCKS OF
GEOMETRY
TODAY’S OBJECTIVES
• Learn the terminology and notation of points,
segments, lines, rays, planes, angles, and collinear
and coplanar points.
• Learn the idea of congruence of line segments
• Learn how to mark congruence of segments on
diagrams
• Begin keeping a notebook of definitions
• Develop Problem Solving Skills
UNDEFINED TERMS
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Point
Line
Plane
The three most basic building blocks of geometry.
POINT
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Has no size.
Only has location
Represented with a dot
Named by a capital letter
LINE
• Straight continuous arrangement of infinitely many
points.
• Has infinite length but no thickness
• Extends forever in two directions
• Named by the letter names of any two points on
the line and the line symbol.
PLANE
• Has length and width, but no thickness.
• Flat surface that extends infinitely along its length
and width.
• Represented with a 4-sided figure, like paper.
• Named with a script capital letter.
• P
ANCIENT “DEFINITIONS”
• “A point is that which has no part. A line is
breadthless length.” –Greeks
• “The line is divided into parts, and that part which
has no remaining part is a point.” –Chinese
IMPOSSIBLE TO DEFINE
• We would have to use the terms point, line, and
plane to define them.
• So we accept them as undefined and use them to
define everything else in Geometry.
COLLINEAR
• On the same line.
COPLANAR
• On the same plane
RAY
• Part of a line
• Has an endpoint but extends forever in one
direction.
ANGLE
• Made up of two rays who share an endpoint.
LINE SEGMENT
• Consists of two endpoints of the segment and all
the points between them that are collinear with the
two points.
CONGRUENT
• Two segments are congruent if they have equal
measures or lengths.
PRACTICE
PRACTICE
PRACTICE
TODAY’S OBJECTIVES
• Learn the terminology and notation of points,
segments, lines, rays, planes, angles, and collinear
and coplanar points.
• Learn the idea of congruence of line segments
• Learn how to mark congruence of segments on
diagrams
• Begin keeping a notebook of definitions
• Develop Problem Solving Skills
EXIT SLIP
1. Draw and mark a figure in which M is the midpoint
of ST, SP=PT and T is the midpoint of PQ.
2. Explain your reasoning.
3. Draw an example of collinear points.
4. Define coplanar.