Instructional Video1:58
CK-12 Foundation

Alternate Interior Angles: Lesson

9th - 12th Standards
Concepts of alternate interior angles parallel the concepts of corresponding angles. Using a diagram, the presentation defines and identifies alternate interior angles formed by a transversal and two parallel lines. The video in a...
Instructional Video2:28
CK-12 Foundation

Corresponding Angles: Lesson

9th - 12th Standards
Take a parallel view of correspondence. The resource, part of a playlist on basic geometry, introduces the corresponding angle postulate. By first identifying corresponding angles, the video highlights the relationship between the angle...
Instructional Video2:23
CK-12 Foundation

Perpendicular Lines: Lesson

9th - 11th Standards
Perpendicular lines are all right. Using the definition of perpendicular, the video lesson introduces perpendicular lines.The portion a basic geometry playlist makes connections between the rules of parallel lines and perpendicular lines.
Instructional Video5:44
CK-12 Foundation

Parallel and Skew Lines: Lesson

7th - 11th Standards
Is it possible for a pair to be parallel and skew? The resource provides the class opportunities to find out by examining the properties of parallel and skew lines. Part of a playlist on basic geometry, the video includes a brief...
Instructional Video3:11
CK-12 Foundation

Two-Column Proofs: Lesson

9th - 12th
Why is it a two-column proof? A video introduces the class to the concept of a two-column proof and how to set one up. The segment of a playlist on basic geometry highlights the types of reasons that can be in a proof.
Instructional Video5:54
CK-12 Foundation

Properties of Equality and Congruence: Lesson

6th - 11th
What properties of equality also work for congruence? Part of basic geometry playlist, the video relates algebraic properties to their counterparts of congruence. Learners see how the properties mean the same whether with equality or...
Instructional Video2:09
CK-12 Foundation

Conjectures and Counterexamples: Lesson

9th - 11th
The first five are red, so they all must be red, right? As part of a larger playlist on basic geometry, the video walks through an example of a conjecture and counterexamples by using a scenario of pulling candy out of a bag.
Instructional Video4:28
CK-12 Foundation

Converse, Inverse, and Contrapositive: Lesson

9th - 12th
Is it true? Use an inquisitive resource to find the truth of related statements. Using short-hand notation, the video shows how to write the converse, inverse, and contrapositive of a conditional statement. The segment a larger geometry...
Instructional Video3:01
CK-12 Foundation

If - Then Statements: Lesson

6th - 12th
If the hypothesis is true, then the conclusion is true too. The presentation, part of a larger playlist on geometry, introduces conditional statements. The resource shows how to rewrite a statement into if-then format and how to identify...
Instructional Video5:48
CK-12 Foundation

Deductive Reasoning: Lesson

6th - 12th
It is elementary, my dear Watson. A segment in a playlist on geometry introduces the idea of deductive reasoning. The video goes over three rules that apply to deductive reasoning and conditional statements.
Instructional Video4:36
CK-12 Foundation

Inductive Reasoning: Lesson

6th - 12th
Let's get specific about the general conclusion. The video, a portion of an extensive geometry playlist, introduces inductive reasoning. Using patterns, the resource explains how inductive reasoning goes from the specific to general.
Instructional Video4:01
CK-12 Foundation

Classifying Polygons: Lesson

4th - 8th Standards
For your eyes only: classify the names of polygons. After providing the definition of a polygon, the video introduces the two major classifications of polygons, concave and convex. The segment of a larger playlist on geometry continues...
Instructional Video4:55
CK-12 Foundation

Classifying Triangles: Lesson

4th - 8th Standards
That's correct, it is right and scalene. The video introduces the two methods for classifying triangles, sides, and angles. A resource in the playlist for basic geometry provides the definitions for each of the classifications.
Instructional Video2:52
CK-12 Foundation

Vertical Angles: Lesson

6th - 10th Standards
Define angles across from each other. An informative segment from a larger playlist on geometry introduces vertical angles and shows they have equal measures. Using their properties, the presenter solves problems involving vertical angles.
Instructional Video2:56
CK-12 Foundation

Supplementary Angles: Lesson

6th - 10th Standards
Supplement your knowledge of angles. Part of a playlist exploring geometry concepts, an interesting video introduces the definition of supplementary angles. Using the definition, the presentation shows how to find the supplement to a...
Instructional Video2:18
CK-12 Foundation

Linear Pairs: Lesson

6th - 10th Standards
Place angles in a line. Part of a playlist on basic geometry, an informative video teaches pupils the definition of a linear pair and how to identify them. Using their properties, the resource demonstrates how to solve problems involving...
Instructional Video3:01
CK-12 Foundation

Complementary Angles: Lesson

6th - 10th Standards
Complement the angle definition. The resource, a video within a basic geometry playlist, introduces the definition of complementary angles. Using the definition, the presentation finds complements of given angles.
Instructional Video3:03
CK-12 Foundation

Classifying Angles: Lesson

4th - 8th Standards
It's time to put the angles in place. Using diagrams, the video presents the basic definitions of the four classifications of angles. The segment in an informative playlist on basic geometry also provides informal descriptions of the...
Instructional Video4:45
CK-12 Foundation

Measuring Angles: Lesson

4th - 6th Standards
Develop a degree of measurement. With the aid of a protractor, the video shows how to measure angles. The segment of a larger playlist on geometry basics points out that it is possible to start at a value other than zero when measuring...
Instructional Video4:19
CK-12 Foundation

Measuring Distances: Lesson

5th - 8th Standards
Let's rule the coordinate plane. By reviewing the marking on rulers, the video discusses how to determine the measurement between two points. The resource, a portion of a basic geometry playlist, determines the length of a side of a...
Instructional Video6:26
CK-12 Foundation

Basic Geometric Definitions: Lesson

4th - 8th Standards
Build up the basics of geometry, one point at a time. The segment in an extensive playlist on basic geometry provides the definitions of the essential building blocks of geometry. Using drawings, the video shows examples and descriptions.
Instructional Video5:25
CK-12 Foundation

Midpoints and Segment Bisectors: Lesson

6th - 10th Standards
Let's meet in the middle. As part of a comprehensive playlist on basic geometry, the video introduces the definitions of a midpoint and segment bisector. The resource shows a graphical approach to finding the midpoint of a line segment...
Instructional Video
CK-12 Foundation

Ck 12: Episd: How Earth Formed

9th - 10th
[Free Registration/Login may be required to access all resource tools.] View a National Geographic video featuring the way the Earth was formed. [1 hr. 30 min.]
Instructional Video
CK-12 Foundation

Ck 12: Characteristics of Life

9th - 10th
[Free Registration/Login may be required to access all resource tools.] An instructional video discussing general characteristics of life with examples. [6:08]