Sophia Learning
Sophia: Right Angles
Right angles are defined in this video lesson. Take quiz to assess learning. [1:32]
Khan Academy
Khan Academy: Geometry: Finding More Angles
Solving for measures of the angles in a triangle using algebra, the triangle sum theorem, and properties of angles created by a transversal that cuts parallel lines. [6:05]
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: 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 Find a Value for X That Makes Two Lines Parallel?
This tutorial shows you how to find x so two lines are parallel. [2:47]
Virtual Nerd
Virtual Nerd: What Are Parallel Lines?
Lines that are parallel have a very special quality. This tutorial takes a look at parallel lines and how they are different from other types of lines. [4:06]
Khan Academy
Khan Academy: Parallel and Perpendicular Lines
Demonstrates how to identify parallel and perpendicular lines in geometric drawings. [3:34]
Virtual Nerd
Virtual Nerd: What Are Skew Lines?
This video tutorial introduces skew lines which are two lines that do not intersect and are not parallel. [3:46]
Study Pug
Study Pug: Perpendicular Line Proofs
Video lesson explains angles, lines, and transversals. [9:33]
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]
Khan Academy
Khan Academy: Find Measure of Vertical Angles
Demonstrates how to find unknown angles for two intersecting lines when some angle information is given. [3:00]
Virtual Nerd
Virtual Nerd: What Are Vertical Angles?
Vertical angles are always congruent to one another. Take a look at this tutorial to learn about and see how to identify vertical angles. [4:07]
Virtual Nerd
Virtual Nerd: What Are Complementary Angles?
Complementary angles always add up to 90 degrees. Watch this tutorial to learn about complementary angles and see how to use this knowledge to solve a problem involving these special types of angles. [3:20]
Virtual Nerd
Virtual Nerd: What Is an Angle?
Take a look at this tutorial to learn about how an angle is formed, how to name an angle, and how an angle is measured. [4:45]
Virtual Nerd
Virtual Nerd: How Do You Find Angle Measures for Adjacent Angles?
In this tutorial, students will learn how to find missing angle measurements by first creating an equation. [4:20]
Virtual Nerd
Virtual Nerd: How Do You Use Supplementary Angles to Find a Missing Angle?
In this tutorial, you'll see how to use your knowledge of supplementary angles to set up an equation and solve for a missing angle measurement. [3:41]
Virtual Nerd
Virtual Nerd: What Are Supplementary Angles?
Take a look at this tutorial as it introduces you to supplementary angles and shows you how to use them to solve for a missing angle measurement. [3:20]
Sophia Learning
Sophia: Perpendicular Lines
Discover the difference between perpendicular lines and intersecting lines. Assess understanding with a quiz.
Sophia Learning
Sophia: Perpendicular Lines
This lesson defines perpendicular lines and gives an assessment to check understanding.
Khan Academy
Khan Academy: Geometry: Similar Triangles
Explains what it means for two triangles to be similar. Diagram of similar triangles is created with two parallel lines cut by two transversals. [9:34]