CK-12 Foundation
Trapezoids: Lesson
Using the definition of a trapezoid, the segment within a large playlist on basic geometry explains other properties of trapezoids. The video introduces the special properties held by isosceles trapezoids.
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...
Corbett Maths
Radius and Tangent – Proof
A tangent line always finds its place at a 90-degree angle to a radius. Many scholars struggle with the proof of the seemingly simple statement. A brief video demonstrates the reasoning behind the proof before pupils practice applying it...
Curated OER
How Do You Find the Area of a Trapezoid?
Trapezoids can be tricky! Break down the process of finding the area of a trapezoid with an engaging math video. Learners explore area formula and shown exactly how to plug in information, solve, and simplify.
Khan Academy
SAT Prep: Test 3 Section 2 Part 4
Finding perimeters and slopes is the focus of this video, which details ways to solve problems 15-17 on the practice SAT. Even students who are confident in their ability to pass the SAT would benefit from this additional review.
CK-12 Foundation
Properties of Equality and Congruence: Lesson
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...
Flipped Math
Parallelogram Properties
Provide pupils with problems on applying properties of parallelograms. The second of seven installments in the Geometry - Quadrilaterals and Polygons unit focuses on parallelograms. Viewers of the instructional video learn about the...
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...
Scholastic
Study Jams! Classify Quadrilaterals
Face the vertex of two-dimensional shapes and discover what each figure requires as part of its classification. With one shape per slide, learners see what makes each shape special and compare it to others with similar qualities.
Brightstorm
Inductive Reasoning
Learners use inductive reasoning every day but might not realize it. An instructive video demonstrates that the process of inductive reasoning means searching for and identifying patterns. The instructor begins with numeric...
Virtual Nerd
What is an Ellipse?
This video answers the question, What is an ellipse? It gives a definition of an ellipse, shows the ellipses relation of a plane to a cone, and the names of different parts of the ellipse.
Curated OER
Circles: Radius, Diameter and Circumference
Fascinating discussion regarding the origin of Pi accompanies a detailed explanation of how to find the circumference of a circle. Since this is the first installment in a series on circles, the concept of circumference is separated into...
Khan Academy
Khan Academy: Geometry: Corresponding Angle Equivalence Implies Parallel Lines
Proof by contradiction that if two lines cut by a transversal create congruent corresponding angles then the lines are parallel. [5:18]
Khan Academy
Khan Academy: Geometry: Triangle Angle Example 2
Shows how to find the measure of missing angles using the triangle sum theorem and vertical angles. This video also appears in the Geometry: Triangles strand. [4:55]
Sophia Learning
Sophia: Proving Lines Perpendicular With Adjacent Congruent Angles
If lines are perpendicular then two intersecting lines form adjacent angles. Assess learning with a quiz.
Khan Academy
Khan Academy: Geometry: Proof Sum of Measures of Angles in a Triangle Are 180
Proof that the sum of the angles in a triangle is 180 using the relationship of angles formed when parallel lines are cut by a transversal. This video also appears in the Geometry: Triangles strand. [6:31]
Khan Academy
Khan Academy: Geometry: Ca Geometry: Deductive Reasoning
Demonstrates solutions to problems #1-3 of California Geometry released state test questions. Problems address understanding of deductive reasoning and congruent angles created by parallel lines cut by a transversal. [10:17]
Khan Academy
Khan Academy: Geometry: Ca Geometry: More Proofs
Demonstrates solutions to problems #7-10 of California Geometry released state test questions. Problems address understanding of congruent angle pairs when parallel lines are cut by a transversal, counterexamples, and properties of the...
Khan Academy
Khan Academy: Geometry: Ca Geometry: Triangles and Parallelograms
In this video lesson [11:14], the instructor demonstrates solutions to problems #21-25 of California Geometry released state test questions. Problems address understanding of the triangle inequality theorem, angle relationships with...
Khan Academy
Khan Academy: Geometry: Angles at the Intersection of Two Lines
Explains how to determine the measures of angles formed by interecting lines when given the measure of one angle. [7:19]
Khan Academy
Khan Academy: Geometry: Example Involving Isosceles Triangle and Parallel Lines
Demonstrates how to use the triangle sum theorem, properties of isosceles triangles, and special angle pairs formed when parallel lines are cut by a transversal to set up an equation using given algebraic expressions for angle measures...
Khan Academy
Khan Academy: Geometry: Two Column Proof Showing Segments Are Perpendicular
In this video tutorial [11:06], the instructor shows how to construct a two-column proof using triangle congruence postulates to prove that two line segments are perpendicular.
Virtual Nerd
Virtual Nerd: How Do You Use Complementary Angles to Find a Missing Angle?
View this tutorial to see how to use what you know about complementary angles to find a missing angle measurement. [3:20]
Virtual Nerd
Virtual Nerd: How Do You Find Missing Angles in a Transversal Diagram?
Take a look at this tutorial to see how to find all the missing angle measurements by identifying vertical, corresponding, adjacent, and alternate exterior angles. [4:43]