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: 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.
Khan Academy
Khan Academy: Geometry: Angles of Parallel Lines 2
Explains how to determine the measures of all the angles formed when parallel lines are cut by a transversal based on the measure of one angle. Explains how to use corresponding congruent angles to determine if lines cut by a transversal...
Khan Academy
Khan Academy: Angles, Parallel Lines, & Transversals
Looks at parallel lines and intersecting lines (transversals), and the angles they form. [7:08]
Virtual Nerd
Virtual Nerd: What Are Perpendicular Lines?
The angles formed by perpendicular lines will always be the same. Take a look at this tutorial to learn about perpendicular lines and see a special trick involving them. [5:22]
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: 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: 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]
PBS
Pbs: Measurement and Geometry: Angles: Vertical and Congruent
Vertical angles lie diagonally opposite one another at an intersection and are always equal in measure. This makes them congruent.
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: 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.
Virtual Nerd
Virtual Nerd: What Is a Point?
Points are needed to make lines, planes, angles, or polygons. and also for graphing. Watch this tutorial to learn about points. [3:50]
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]