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TODAY’S GOAL: to identify, name & draw points, lines, segments, rays and planes
_______________: an instant in space; a location represented by a dot; has no size; labeled with a
capital letter; it takes up no space  considered “UNDEFINED” in Geometry
.
A
_______________: an infinite set of points; no thickness; straight; continues forever in opposite
directions; labeled by a single lower case letter or by any two points on the line;
has no particular thickness  also considered “UNDEFINED” in Geometry
line
l
OR
_______________: flatness; a flat surface; no thickness; extends in all directions without end; labeled
with a single capital letter or any three points not in the same line on the plane;
has no thickness  this is the 3rd “UNDEFINED” term in Geometry
plane P or plane DEF
P
E
D
F
 just to recap, the 3 undefined terms in Geometry are: ____________, ______________ and
_______________
_________________: the set of all points
_________________________: points that lie on the same line
_________________________: points that do not lie on the same line
_________________________: points that lie in the same plane
_________________________: points that do not lie in the same plane
__________________: the part of a line consisting of two points and all the [possible] points in
between them
{draw & name it in this space}
_________________: a point at one end of a segment or the starting point of a ray
{draw in this space}
__________: the part of a line that starts at an endpoint and extends forever in one direction
{draw & name it in this space}
_________________________: two rays with a common endpoint that form a line
{draw & name them in this space}
Ex. 1: Draw and label a segment with endpoints M & N
Ex. 2: Draw and label a ray with endpoint F that passes through G.
Ex. 3: In this figure, name the following:
B
C
A
M
A.) a line that contains A and C
____________________________________
B.) the plane that contains A, C and D
________________
C.) three collinear points
________________
D.) three noncollinear points
________________
E.) a ray with endpoint D
________________
F.) all segments shown
________________
_______________ (or _____________): statements accepted without proof
Postulate 1: Through any two points there is exactly one line.
. .
Postulate 2: Through any three noncollinear points there is exactly one plane containing them.
A
B
C
Postulate 3: If two points lie in a plane, then the line containing those points lies in the plane.
_____________________: the set of all points that two or more figures have in common
Postulate 4: If two lines intersect, then they intersect in exactly one point.
 real-life example: ________________________
Postulate 5: If two planes intersect, then they intersect in exactly one line.
 real-life example: ________________________
Ex. 4: Sketch three coplanar lines that intersect in a common point.
Ex. 5: Sketch a line intersecting a plane but where the line doesn’t lie in the plane.