# Ch 1: Big Ideas Math Geometry Chapter 1: Basics of Geometry

### About This Chapter

## How It Works:

- Find the lesson within this chapter that corresponds to what you're studying in the Basics of Geometry chapter of your textbook.
- Watch fun videos that cover the basic geometry concepts you need to learn or review.
- Complete the quiz after watching each video lesson to test your understanding.
- If you need additional help, rewatch the videos until you've mastered the material, or submit a question for one of our instructors.

## Chapter Topics

You'll learn all of the geometry topics covered in the textbook chapter, including:

- Unidentified terms
- Examples of line segments
- Measuring distance and midpoint
- Concave and convex polygons
- Finding perimeter and area
- Measuring different types of angles

*Big Ideas Math is a registered trademark of Larson Texts, Inc., which is not affiliated with Study.com.*

### 1. Undefined Terms of Geometry: Concepts & Significance

What do points, lines, planes, and sets have in common? Watch this video lesson to find out what they are, what they look like, and why they are called undefined terms.

### 2. Line Segments & Rays: Definition & Measurement

Watch this video lesson to learn the difference between a line segment and a ray. You will also learn how to measure and add line segments. Learn why you can't measure or add a ray.

### 3. Ruler Postulate: Definition & Examples

This lesson explains the definition of the ruler postulate. You'll see several examples that use the ruler postulate. Then, you can check your knowledge with a quiz.

### 4. Congruent Segments: Definition & Examples

In this lesson, you will learn the definition of congruent segments. You will be given examples of congruent segments to further your understanding of the material. Following this lesson will be a brief quiz to test your new knowledge on this subject.

### 5. Segment Addition Postulate: Definition & Examples

In this lesson, we will review the definition of the segment addition postulate. We will also look at examples to clearly illustrate how this concept works in the real-world.

### 6. Line Segment Bisection & Midpoint Theorem: Geometric Construction

Watch this video lesson and you will learn how to bisect a line segment without measurements using just a compass and a straight edge. You'll also learn about the midpoint theorem, which lets you calculate the midpoint if you have the measurements.

### 7. How to Use The Midpoint Formula

The formula for the midpoint of a line segment will tell you how to find the middle of any line segment on the x, y plane. Learn about this formula and see how it is used to find the midpoint of a line segment.

### 8. How to Find the Distance Between Two Points

After watching this video lesson, you will be able to find the distance between any two points on the coordinate plane. Learn what information you and how to plug them in to your formula.

### 9. Concave & Convex Polygons: Definition & Examples

In this lesson, we'll explore one of the main ways of classifying polygons - as convex or concave. We'll also learn how you can determine if a polygon is convex or concave.

### 10. Perimeter & Area in the Coordinate Plane

After reading this lesson, you'll know how you can use the coordinate plane to help you find the perimeter and area of various shapes. Learn how you can find your answers just by counting.

### 11. How to Measure Angles with a Protractor

You're surrounded by angles at home, at school, and even when you're walking down the street. In this lesson, you'll learn how to measure different angles using a protractor.

### 12. What is a Right Angle? - Definition & Formula

In this lesson, you will learn about the properties that identify right angles. You will also discover where right angles can be found and learn about what makes them so useful. You can then test your knowledge with a quiz.

### 13. What is an Acute Angle? - Definition, Description & Examples

In this lesson, you'll learn what makes an angle acute and see a few different examples of them. After the lesson, you can test your new knowledge with a brief quiz.

### 14. What is an Obtuse Angle? - Definition & Examples

In this lesson, you'll learn what angles, right angles, and obtuse angles are; you'll see a few examples of different obtuse angles. Test your knowledge with a brief quiz once you've completed the lesson.

### 15. Congruent Angles: Definition & Examples

In this lesson, we'll explore the definition of a congruent angle. You'll learn how to draw a congruent angle, explore examples of congruent angles, and test your knowledge with a short quiz.

### 16. Angle Addition Postulate: Definition & Examples

In this lesson, you will learn the definition of the Angle Addition Postulate. We will look at some examples so that you understand how this postulate works.

### 17. Constructing an Angle Bisector in Geometry

Watch this video lesson to learn a cool way to split an angle in half. You can use this method to split a pie slice in half where you can be sure each side is equal.

### 18. Angle Pairs: Types & Concept

There are five major types of angle pairs in geometry. In this lesson, you'll explore the different types of angles and learn the rules of measuring those angles. When you finish the lesson, test your knowledge with a short quiz.

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### Other Chapters

Other chapters within the Big Ideas Math Geometry: Online Textbook Help course

- Big Ideas Math Geometry Chapter 2: Reasoning and Proofs
- Big Ideas Math Geometry Chapter 3: Parallel and Perpendicular Lines
- Big Ideas Math Geometry Chapter 4: Transformations
- Big Ideas Math Geometry Chapter 5: Congruent Triangles
- Big Ideas Math Geometry Chapter 6: Relationships Within Triangles
- Big Ideas Math Geometry Chapter 7: Quadrilaterals and Other Polygons
- Big Ideas Math Geometry Chapter 8: Similarity
- Big Ideas Math Geometry Chapter 9: Right Triangles and Trigonometry
- Big Ideas Math Geometry Chapter 10: Circles
- Big Ideas Math Geometry Chapter 11: Circumference, Area, and Volume
- Big Ideas Math Geometry Chapter 12: Probability