A logical statement that has two parts: IF (hypothesis/antecedent/premise) and THEN (conclusion)
Hypothesis
Antecedent or premise (P)
Conclusion
Consequence (Q)
Types of conditional statements
Prime (only one factor)
Composite (two or more factors)
Even
Not divisible by 2
Odd
Divisible by 2
Inverse
not p + not q
Converse
q + p
Contrapositive
not q + not p
Conditional
P + Q
Euclid
First described geometry as a mathematical system through his textbooks
Geometry refers to a structure formed from a set of undefined, definitions (defined terms), accepted properties, theorems, and axioms
Mathematical system
A structure formed from a set of undefined terms or agreements, valid definitions, accepted properties, and postulates which you can apply to derive new concepts, properties, and theorems through deductive reasoning
Important parts of a mathematical system
Undefined terms
Definitions
Postulates
Accepted properties
Accepted theorems
Undefined terms
Do not have formal definitions, can only describe their features
Definition
A statement that describes the meaning of known words
Collinear points
Points that lie on the same line
Coplanar points
Points that lie on the same plane
Ray
Has one endpoint and extends infinitely in one direction
Intersection points
The collection of common points between two or more geometric figures
Betweenness of a point
If three points are collinear, then one point is between the other two points
Congruent segments
Two line segments that have the same length
Coplanar Points
Points that lie on the same plane
Line Segment
The union of points A, B, and all the points between them
Ray
Has an endpoint and extends infinitely in one direction
Intersection Points
The collection of common points between two or more geometric figures
Distance between Two Points
The length of the line segment that connects the two points
Midpoint
The point that divides a line segment into two congruent line segments
Segment Bisector
A point, ray, line segment, line, or plane that intersects the line segment at its midpoint
Angle
The union of two noncollinear rays with a common endpoint, where the rays are the sides of the angle and the common endpoint is the vertex
Acute Angle
An angle that measures greater than 0 but less than 90 degrees
RightAngle
An angle that measures exactly 90 degrees
Obtuse Angle
An angle that measures greater than 90 but less than 180 degrees
Straight Angle
An angle that measures exactly 180 degrees
Congruent Angles
Two angles with equal measures
Angle Bisector
A ray that divides an angle into two congruent angles
Complementary Angles
Two angles whose measures sum to 90 degrees
Supplementary Angles
Two angles whose measures sum to 180 degrees
Adjacent Angles
Two angles that share a common vertex and side, but have no common interior points
Linear Pair
Two adjacent angles whose noncommon sides are opposite rays