Flipped Math
AAS and ASA
Sometimes one knows more about angles than about sides. Young mathematicians learn about the AAS and ASA triangle congruence criteria by watching an informative video. They use these shortcuts to demonstrate triangle congruence in...
Flipped Math
Unit 3 Review: Parallell and Perpendicular Lines
Learners watch a quick review on the Parallel and Perpendicular Lines unit. The pupils work through ten review problems ranging from identifying types of angles formed by parallel lines and transversals to writing equations of parallel...
Flipped Math
Unit 4 Review: Triangle Congruence
It's time to prove one's knowledge of triangle congruence proofs. Scholars watch a video to review triangle classifications and how to use properties of triangles to set up and solve equations for missing values. They also review the...
Flipped Math
CPCTC and HL Theorem
The resource is sure to be a right fit for introducing the congruence of right triangles. The fourth of five lessons in the Geometry - Triangle Congruence unit teaches pupils how to use CPCTC to prove congruent parts. They also apply the...
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
Triangles
Take time to tackle triangles. Scholars watch a video that first reviews the types of triangles. They then investigate the Isosceles Triangle Theorem and see how to apply it to solve problems. At the end, individuals also learn how to...
Flipped Math
Parallel Lines and Triangles
Triangles bring sums to geometry. The lesson presents two theorems dealing with the angles of a triangle. Pupils learn about the Triangle Sum Theorem and the Exterior Angle Theorem, and then apply the theorems to create equations and...
CK-12 Foundation
Medians: Examples
Balance the knowledge of intersecting medians. Using examples, the portion of a geometry playlist introduces the centroid. A video describes the property of the location of the triangle medians' point of concurrency.
CK-12 Foundation
Altitudes: Examples
Find the location of altitudes—from any elevation! The video presents the definition of an altitude of a triangle. By drawing examples, the segment of a larger geometry playlist highlights the location of altitudes of various triangle...
CK-12 Foundation
Equilateral Triangles: Lesson
Take a second look at triangles that are equal all the way around. The video reminds viewers what an equilateral triangle is and points out that the three angles are the same. Using the fact that equilateral triangles are also isosceles,...
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
The Third Angle Theorem: Lesson
If two sets of angles are equal, the third set is too. An informative portion of a playlist on geometry develops the Third Angle Theorem for triangles. Using the theorem, the presenter shows how to determine the measure of missing angles...
CK-12 Foundation
Midsegment Theorem: Lesson
Use half the length to connect the midpoints. A section of a playlist on geometry introduces the concept of a midsegment of a triangle and how to find it. The video states the properties of the midsegment which make up the Midsegment...
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.
Mathed Up!
Angles in Polygons
Show your class that finding angle measures is a regular calculation with a resource that provides 12 problems dealing with the measures of angles in regular polygons. Pupils use formulas for the sum of measures of angles in a polygon to...
Mathed Up!
Angles in Triangles and Quadrilaterals
This short video show viewers how to connect the sum of the angles in a triangle to other angle measurements. Pupils determine the missing measures for angles involved with triangles and quadrilaterals. Class members then must explain...
Krista King Math
The Isosceles Triangle Theorem is Actually Really Simple!
The isosceles triangle comes with its own set of properties. A lecturer shows how to apply the Isosceles Triangle Theorem to find missing side lengths or angle measures. The final example involves both square roots and quadratic...
Krista King Math
Line Segments in 3-D: Finding the Midpoint!
It's about to get 3-D! The video shows your class how to expand the midpoint formula to find the midpoint of a three-dimensional segment. The example shown calculates the midpoint using the x-, y-, and z-coordinates.
Brightstorm
Triangle Angle Sum
Don't believe everything that you hear — make them prove it! The video shows two methods to prove the Triangle Angle Sum Theorem. The following two videos apply the theorem to finding missing angle measures.
Khan Academy
Khan Academy: Geometry: Equilateral Triangle Sides and Angles Congruent
In this video tutorial [6:29], the instructor models a proof so show that if the sides of an equilateral triangle are congruent, then all the angles are congruent and vice versa. The instructor uses the knowledge of congruent legs and...
Khan Academy
Khan Academy: Geometry: Ca Geometry: Proof by Contradiction
Demonstrates solutions to problems #4-6 of California Geometry released state test questions. Problems address understanding of proof by contradiction and proving triangles congruent. [11:56]
Khan Academy
Khan Academy: Geometry: Congruent Triangle Proof Example
Demonstrates how to use triangle congruency to prove that a given point is the midpoint of a given line segment. The proof is written in the form of a two-column proof. Practice problems available. [5:46]
Khan Academy
Khan Academy: Geometry: Congruent Parts of Iscosceles Triangles
Proof that if the legs of an isosceles triangle are congruent then the base angles are congruent and vice versa using triangle congruency postulates. The proof is written as a two-column proof. [9:03]
Khan Academy
Khan Academy: Geometry: Congruent Triangle Example 2
Demonstrates how to use triangle congruency to prove that corresponding sides of congruent triangles are congruent and then identifies other congruent parts in the overlapping triangle diagram. The proof is written in the form of a...