Term

Definition
represents a position in space or on a plane
has no size represented by a dot
labeled with an upper case letter
. P 


Term

Definition
figure that extends forever in 2 directions
NO ENDPOINTS
Named with any 2 of its points' letters under a ↔ OR
by line and an italiziced letter put near line to name.
[image] 


Term
line segment or simply
segment 

Definition
part of a line that is between and including 2 endpoints
Named by its 2 endpoints in any order under ‾‾. 


Term

Definition
Part of line that is on one side of a point of that line.
Named with its initial (or ENDPOINT) FIRST and then any point through which the ray goes under a →.
[image]



Term

Definition
points that could lie on one line.
Here, the red points are collinear, the gray points are noncollinear because they cannot all lie on only 1 line
[image]



Term

Definition
the common point or points shared by 2 figures
[image] E is the intersection of line AD and line BC.
[image] The blue line is the intersection of plane M and plane S. 


Term

Definition
distance between Points M and J .
if on a number line the absolute value of the difference of the coordinates of the endpoints.
 coordinate of M minus coordinate of J
Will always be positive or 0.
BE CAREFUL WITH NEGATIVES. 


Term

Definition
If C is between A and B, then AC + CB = AB.
part segment + other part = entire segment in question
[image]



Term

Definition
segments, angles or figures having equal SIZE AND SHAPE.
@ means congruent
Congruent segments are shown on drawings by the same number of tick marks on congruent segments.
Congruent angles are shown the same way OR by having the same number of arcs.



Term

Definition
The point that divides a segment into 2 congruent segments. If M is the midpoint of segment AB
[image]
AM = MB 


Term

Definition
figure formed by 2 rays that share the same initial or endpoint.
Rays are the sides, vertex is point shared by both.
Angles are named with a single number or the letter for the vertex point if they are isolated. If it is not clear which angle is meant, 3 letters are needed: the letters for the vertex and a point on each side of the angle. This angle could be named ÐACB, ÐBCA orÐC



Term

Definition
A complete rotation contains 360°.
Ancients believed that it took the sun 360 days to circle the earth.
Be glad that they did not know that it takes 365 1/4 days for the earth to circle the sun.
Degrees measure how open an angle is, not how long the sides are. 


Term

Definition
An angle that forms a straight line with its vertex somewhere on that line.
It contains half a rotation or half of 360°.
A straight angle contains 180°.[image] 


Term

Definition
an angle that contains 1/4 of a complete rotation or 90°.
The corner of this index card is a right angle.
A square box inside an angle shows that the angle is a right angle.
[image] 


Term

Definition
An angle that is more than 0° and less than 90 ° .
[image]
These are cute, little angles. 


Term

Definition
An angle that is more than 90° and less than 180 °
[image]
This angle is obese or bigger than a right angle, but less than
a straight angle. 


Term

Definition
the length between 2 points P_{1} and P_{2} on a Cartesian graph.
Label the coordinates CAREFULLY
( x_{1}, y_{1}) and (x_{2}, y_{2}).
Then sub into
[image]



Term

Definition
If A (x_{1}, y_{1}) and B (x_{2},y_{2}) are points in a coordinate plane, then the midpoint of line segment AB has the coordinates
[image] 


Term

Definition
if M is the midpoint of AB, then
AM = MB = ½ of AB
[image]



Term

Definition
a ray that divides an angle into 2 adjacent angles that are congruent ( have equal measures)
Ray BD bisects ÐABC since it divides the angle into 2 congruent angles ÐABD and ÐDBC; mÐABD = mÐDBC
[image] 


Term

Definition
When 2 lines intersect, the 2 pairs of opposite angles are vertical Ðs. Form BUTTERFLY WINGS or
A BOWTIE
Ð1 & Ð3are vertical Ðs ; Ð2 &Ð4 are vertical Ðs
[image] 


Term

Definition
If point D is in the interior ofÐABC,
then mÐABD + mÐDBC = mÐABC
m partÐ+ m partÐ =m entireÐ
[image] 


Term

Definition
the 2 Ðs formed when the endpoint of a ray falls on a line.
(2 adjacent Ðs whose noncommon sides are opposite rays.)
[image]
Ð ADB and ÐBDC form a linear pair and will add to 180°
Special case of angle addition. 


Term

Definition
2 angles whose measures add to 90^{ o}
Complementary Corner Add to 90^{o}
[image] 


Term

Definition
two angles whose measures add to 180 degrees.
Supplementary make a Straight Line
and/or Add to 180^{o}
[image]



Term

Definition
angles that share a common vertex and side, but no interior points



Term

Definition
2 lines that intersect to form right angles.
[image]
Symbol: ^
GE ^ DF 


Term

Definition


Term
midpoint on a number line 

Definition
Add the coordinates of the endpoints.
Then, divide that sum by 2 to get the midpoint.
x_{2}  x_{1}
2



Term
To find an endpoint when given a midpoint and one endpoint coordinates 

Definition
Label midpoint coordinates (x_{M} , y_{M} )
Label given endpoint (x_{1} , y_{1} )
You are looking for (x_{2} , y_{2} )other endpoint
[image]


