Geometry
Slideshow
POINT
• A point is an exact location in space.
• Say “POINT A”
LINE
• A line is a straight path of points
that goes on and on in two directions.
• Say “LINE AB”
• Write
LINE SEGMENT
• A line segment is a part of a line. It
has two endpoints.
• Say
“LINE SEGMENT AB”
• Write
RAY
• A ray is part of a line. It has one
endpoint and continues on and on in
only one direction.
• Say “RAY FG”
• Write
ANGLE
• An angle is formed by two rays that
have the same endpoint. The common
endpoint is the vertex.
•
•
•
SAY:
1)”Angle A” (vertex)
2) “Angle BAC”
3)”Angle CAB”
• Write
ANGLE
• QUESTION: WHY CAN’T WE CALL THIS
ANGLE CBA or BCA?
• ANSWER: The VERTEX letter must
always be in the center when naming angles
OR just by itself.
• Write
PARALLEL LINES
• Never intersect (cross)
• They are like the sides of a street
• Parallel lines will never meet each other, no matter how
much you continue them in either direction.
INTERSECTING LINES
• Pass through the same point
PERPENDICULAR
LINES
• Lines that intersect and form 4 right
angles.
• The little symbol marked in the corner means
“right angle.”
RIGHT ANGLE
• Measures 90 degrees
• has a square corner
ACUTE ANGLE
• Measures less than a right
angle (90 degrees)
• It’s so cute! (Get it? Tiny? Acute?)
OBTUSE ANGLE
• Measures more than a right
angle (90 degrees)
• Less than 180 degrees
*
Tubas are big and so are obtuse angles!
STRAIGHT ANGLE
• Measures 180 degrees
POLYGONS
• Closed, flat plane figures
with 3 or more lines
segments
• Is a circle a polygon? NO!
TRIANGLE
• 3 sides, 3 vertices
Right
triangle
QUADRILATERAL
• 4 sides, 4 vertices
Square
Rectangle
Trapezoid
Rhombus
Parallelogram
QUADRILATERAL
Square:
all sides
are equal
Rhombus:
Slanted
square
Rectangle:
has 4 right
angles, 2 sets
of parallel lines
Parallelogram:
Slanted rectangle,
opposite sides are
parallel
Trapezoid:
One set of
parallel lines,
one set of
lines that will
intersect
PENTAGON
• 5 sides, 5 vertices
HEXAGON
• 6 sides, 6 vertices
HEPTGON
• 7 sides, 7 vertices
OCTAGON
• 8 sides, 8 vertices
NONAGON
• 9 sides, 9 vertices
DECAGON
• 10 sides, 10 vertices
3D shapes