Ch 12: Geometry and the Properties of Shapes

1. What are 2D Shapes? - Definition & Examples

In this lesson, you will find out how a flat piece of paper will help you determine what shapes are considered 2D. You will also learn the wide variety of 2D shapes you may encounter in life.

2. What are 3D Shapes? - Definition & Examples

What's the difference between 2D and 3D shapes? Learn the answer to this question in this lesson. You will also explore what makes spheres and cubes 3D shapes.

3. 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.

4. 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.

5. 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.

6. 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.

7. Angles of 90, 180, 270 & 360 Degrees

Angles make up the physical structures all around us, from street corners and traffic signs, to buildings, to the chair you're sitting on right now. In this lesson, we will explore the key angles of 90, 180, 270, and 360 degrees as they appear in mathematics and in the structures around us.

8. Rectangles: Definition, Properties & Construction

Watch this video lesson to learn a bit about rectangles. Learn why rectangles are the building blocks of many homes. Also, learn about the properties that make a rectangle unique from other shapes. Finally, learn how you can draw one.

9. What Are Polygons? - Definition and Examples

Watch this video lesson to see how the shapes that you grew up with are all related. Learn why the shapes of bricks, stars, and street blocks are considered polygons while the sun, moon, and rolling hills are not.

10. Measuring the Angles of Triangles: 180 Degrees

Watch this video lesson to see why a triangle's angles always add up to 180 degrees. Also, learn how you can use this unique fact about triangles to find an unknown angle in a triangle.

11. Reflection, Rotation & Translation

This lesson will define reflection, rotation, and translation as they relate to math. It will also show you an example of each one so that you can perform these transformations on your own.

12. Line and Rotational Symmetries of 2-D Shapes

One of the most important concepts in geometry is the idea of symmetry. But what does it actually mean? This lesson explains the difference between line symmetry and rotational symmetry.

13. Graph Functions by Plotting Points

Let's say you have a function. What does it look like? How do you graph it? In this lesson, we'll learn how to graph functions by determining and plotting points.