1. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.

2. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Definitions – statements that distinguish one term from all other terms
Triangle – an enclosed three sided figure
Square – an enclosed four sided figure, all sides have equal measure and all angles are right angles

3. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Definitions – statements that distinguish one term from all other terms
Triangle – an enclosed three sided figure
Square – an enclosed four sided figure, all sides have equal measure and all angles are right angles
Each definition names the term, defines which set it belongs to ( both are figures ), and states the properties that distinguish it from other terms.

4. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Definitions – statements that distinguish one term from all other terms
Triangle – an enclosed three sided figure
Square – an enclosed four sided figure, all sides have equal measure and all angles are right angles
Each definition names the term, defines which set it belongs to ( both are figures ), and states the properties that distinguish it from other terms.
Postulates – statements that are generally accepted as true
Every line contains at least two points.

5. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Definitions – statements that distinguish one term from all other terms
Triangle – an enclosed three sided figure
Square – an enclosed four sided figure, all sides have equal measure and all angles are right angles
Each definition names the term, defines which set it belongs to ( both are figures ), and states the properties that distinguish it from other terms.
Postulates – statements that are generally accepted as true
Every line contains at least two points.
Postulates help us to state simple facts; in this case referring to lines. Postulates help us draw valid conclusions about complex problems. Sometimes they describe relationships between geometric figures.

6. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Theorems – statements that must be proved before they are accepted as being true
Theorem - If two lines are perpendicular, they form four right angles.
To prove this theorem we need to know the definition of perpendicular.
Perpendicular Lines – lines that intersect each other at a 90° angle.

7. Introduction to Geometry – Postulates and Theorems
This first section introduces you to terms that we will be using throughout the course. I would not go about memorizing these but you must understand how they are used. So I would write out the definition of a postulate or theorem, and then describe in your own words how it is utilized.
Theorems – statements that must be proved before they are accepted as being true
Theorem - If two lines are perpendicular, they form four right angles.
To prove this theorem we need to know the definition of perpendicular.
Perpendicular Lines – lines that intersect each other at a 90° angle.
To prove theorems you might need an illustration.
The illustration helps show how the lines are perpendicular

8. Definition of perpendicular
Introduction to Geometry – Postulates and Theorems
Proof – a formal process used to demonstrate the truth of a statement
To prove something in geometry you need to set up a series of logically related statements that lead to some previous conclusion. They are set up as a table…
Statements
Reasons
Definition of perpendicular
Proven theorems, definitions, or postulates

9. Definition of perpendicular
Introduction to Geometry – Postulates and Theorems
Proof – a formal process used to demonstrate the truth of a statement
To prove something in geometry you need to set up a series of logically related statements that lead to some previous conclusion. They are set up as a table…
Statements
Reasons
Definition of perpendicular
Proven theorems, definitions, or postulates
Direct Proof – shows that a statement is true because a logical chain of steps supports it.
Indirect Proof – shows that a statement can not be false, therefore it must be true

10. Statements Reasons Introduction to Geometry – Postulates and Theorems
Let’s set up a simple proof so you can see what it looks like.
Given : AB is intersecting CD at E
AB is perpendicular to CD
Prove : angle AEB = angle CED C A B E D
Statements
Reasons

11. Statements Reasons Introduction to Geometry – Postulates and Theorems
Let’s set up a simple proof so you can see what it looks like.
Given : AB is intersecting CD at E
AB is perpendicular to CD
Prove : angle AEB = angle CED C A B E D
Statements
Reasons
Angles AEC, CEB, BED, and AED are all right angles

12. Statements Reasons Introduction to Geometry – Postulates and Theorems
Let’s set up a simple proof so you can see what it looks like.
Given : AB is intersecting CD at E
AB is perpendicular to CD
Prove : angle AEB = angle CED C A B E D
Statements
Reasons
Angles AEC, CEB, BED, and AED are all right angles
Theorem – if two lines are perpendicular, they form four right angles

13. Statements Reasons Introduction to Geometry – Postulates and Theorems
Let’s set up a simple proof so you can see what it looks like.
Given : AB is intersecting CD at E
AB is perpendicular to CD
Prove : angle AEB = angle CED C A B E D
Statements
Reasons
Angles AEC, CEB, BED, and AED are all right angles
Theorem – if two lines are perpendicular, they form four right angles
Angle AEB = angle CED
Definition – the degree measure of a right angle is 90°