CK-12 Foundation
Indirect Proofs in Algebra and Geometry: Lesson
Indirectly, it is a good proof method. A segment of a playlist on geometry introduces a way to prove geometric and algebraic statements. Using a general examples, the video shows how to develop an indirect proof.
CK-12 Foundation
Classifying Parallelograms: Lesson
Properly organize parallelograms. Given special parallelograms, the narrator of a short video explains the properties of each. The section of a playlist on geometry uses the properties to classify the special parallelograms.
CK-12 Foundation
Triangle Sum Theorem: Lesson
The measures all add up. The presentation, part of a helpful playlist on geometry, provides the statement of the Triangle Sum Theorem. Using the theorem, the video shows how to find the missing measure of an angle.
CK-12 Foundation
Two-Column Proofs: Lesson
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.
Brightstorm
Pythagorean Theorem Proofs
Your class knows the Pythagorean Theorem, but can they prove it? A series of three videos shows two proofs of the Pythagorean Theorem and use it to classify triangles.
CK-12 Foundation
SSS Triangle Congruence: Lesson
Gimme three sides, mister! The video introduces the Side-Side-Side Triangle Congruence Theorem. Using segments of different lengths, the portion of a larger playlist on geometry shows that only one triangle can be built.
CK-12 Foundation
Chords in Circles: Lesson
Strike a chord with four theorems. The segment of a playlist on geometry introduces four basic theorems about chords in a circle. Theorems include the relationships between diameters and chords, congruent chords and arcs, and congruent...
CK-12 Foundation
Parallel Lines and Transversals: Lesson
Segment transversals proportionally. Given a diagram with three parallel lines and two transversals, the narrator of a short video points out the parallel lines cut the transversals proportionally. The portion of a long playlist on...
CK-12 Foundation
SSS Similarity Theorem: Lesson
Judging by the sides, things appear similar. A portion of a larger playlist on geometry introduces the Side-Side-Side Similarity Theorem. The video shows how to use the lengths of sides to determine whether triangles are similar.
CK-12 Foundation
Inscribed Angles in Circles: Lesson
Circle the angles and intercept the arcs. The video introduces three theorems relating to inscribed angles in circles. Using drawings, the segment of a playlist on geometry illustrates the measure of angle along with theorems about two...
CK-12 Foundation
Alternate Exterior Angles: Lesson
Use an alternate approach to parallel lines. A resource in a comprehensive playlist on basic geometry develops the concept of alternate exterior angles and parallel lines. The presentation demonstrates how to identify alternate exterior...
CK-12 Foundation
Alternate Interior Angles: Lesson
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...
CK-12 Foundation
Exterior Angles Theorems: Lesson
Use the inside to find the outside. The resource presents two theorems dealing with exterior angles of a triangle. Using the two theorems, the segment from a larger geometry playlist works problems to solve for angle measures.
CK-12 Foundation
SAS Similarity Theorem: Lesson
When given two sides and an angle, make similar triangles. The video describes the SAS Similarity Theorem. Using the theorem, the segment of a larger geometry playlist determines whether two triangles are similar.
CK-12 Foundation
Triangle AA Similarity: Lesson
Two sets of congruent angles leads to three. Using diagrams of two triangles, the presentation intuitively shows that if two sets of angles are congruent, the third set is too. The portion of a geometry playlist uses that information to...
CK-12 Foundation
Conjectures and Counterexamples: Lesson
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.
CK-12 Foundation
Same Side Interior Angles: Lesson
Supplement your scholars' knowledge of angles involved with parallel lines. Using the properties of alternate interior angles and linear pairs, the presenter shows interior angles located on the same side of a transversal of parallel...
CK-12 Foundation
Isosceles Triangles: Lesson
Two sides give us two angles. A segment of a playlist on basic geometry revisits isosceles triangles. The presentation explains several properties and theorems related to isosceles triangles.
CK-12 Foundation
Proportions with Angle Bisectors: Lesson
Half at one end becomes proportional on the other. As part of a basic geometry playlist, the video introduces the Angle Bisector Theorem. The presentation uses the theorem to find missing lengths in triangles.
CK-12 Foundation
Inscribed Similar Triangles: Lesson
Create similar triangles with a little altitude. A section of an extensive playlist on basic geometry discusses how an altitude of a right triangle creates similar triangles. Using the theorem, the presentation finds unknown side...
TED-Ed
How Many Ways Are There to Prove the Pythagorean Theorem?
There is more than one way to prove the Pythagorean Theorem. Euclid and Einstein found the same way to prove the Pythagorean Theorem. The video introduces several other ways to prove the theorem along with the history of its use.
Flipped Math
SSS and SAS
Why use six corresponding parts when three will suffice? The second of five lessons in the Geometry - Triangle Congruence unit focuses on the SSS and SAS triangle congruence criteria. By watching a video, scholars learn how to identify...
Flipped Math
Conditions for Rectangles, Rhombuses and Squares
Here's a special lesson about some special parallelograms. The fifth of seven parts in the Geometry - Quadrilaterals and Polygons unit focuses on the conditions for rectangles, rhombuses, and squares. Young mathematicians use these...