Download The Language of Geometry: Points, Lines, Rays, Line Segments and

January 11, 2012
The Language of Geometry:
Points, Lines, Rays,
Line Segments and Angles
January 11, 2012
Term:
Point A
Symbol: A
Figure:
⋅A
A point is a position in space.
A point has no size but has a
position.
We usually represent a point
by a small dot.
Points are always labelled by
capital letters
(A, B, C, . . . X, Y, Z)
The cactus's areoles are examples
of points found in nature.
January 11, 2012
Term :
Line AB
Symbol: AB
Figure:
The two-headed arrow over AB indicates
a line passing through points A and B.
We say line AB or line BA.
A line is a straight path that
extends forever in both
directions.
Ridges in the sand are examples
of lines found in nature.
January 11, 2012
Term:
Ray AB
Symbol: AB
Figure:
The one-headed arrow over AB indicates
a ray starting at point A and passing
through point B.
We say ray AB.
A ray is a straight line that
begins at a certain point and
extends forever in one
direction.
The point where the ray begins
is known as its endpoint.
A light beam is an example of a ray
found in nature.
January 11, 2012
Term:
Line Segment AB
Symbol: AB or AB
Figure:
We say line segment AB or
line segment BA.
A line segment is part of a
line. A line segment does not
extend forever, but has two
end points.
The rungs on railroad tracks are line
segments because they have a
beginning and end point.
January 11, 2012
Term:
Angle ABC
Symbol: ∠ABC or ∠CBA
Figure:
Two rays that share the
same endpoint form an
angle. The point where the
rays intersect is called the
vertex of the angle.
The two rays are called
the sides of the angle.
Fallen trees in a forest are examples
of angles found in nature.
January 11, 2012
What geometric
terms do you
see?
January 11, 2012
Questions??