Instructional Video
Khan Academy

Khan Academy: Geometry: Triangle Angle Example 3

9th - 10th
Explains how to solve for multiple missing angles in a diagram composed of multiple triangles using the triangle sum theorem and other angle relationships. This video also appears in the Geometry: Triangles strand. [5:42]
Instructional Video
Khan Academy

Khan Academy: Geometry: Angle Game (Part 2)

9th - 10th Standards
Solving for unknown angle measures using knowledge of different angle relationships and the triangle sum theorem. Continuation of Angle Game video. [9:49]
Instructional Video
Khan Academy

Khan Academy: Geometry: The Angle Game

9th - 10th Standards
Solving for unknown angle measures using knowledge of different angle relationships and the triangle sum theorem. [9:01]
Instructional Video
Khan Academy

Khan Academy: Geometry: Proof Sum of Measures of Angles in a Triangle Are 180

9th - 10th
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]
Instructional Video
Khan Academy

Khan Academy: Geometry: Ca Geometry: Deducing Angle Measures

9th - 10th Standards
Demonstrates how to solve five different problems from a released California Geometry state test that involve finding the measures of angles in different polygons. This video also appears in the Geometry: Worked Examples section. [10:58]
Instructional Video
Khan Academy

Khan Academy: Geometry: Figuring Out All Angles for Congruent Triangles Example

9th - 10th
Explains how to use given triangle congruency statements to determine the unknown measures of all angles in a diagram where one large triangle is divided into three congruent triangles. [4:35]
Instructional Video
Khan Academy

Khan Academy: Geometry: Equilateral and Isosceles Example Problems

9th - 10th
Demonstrates how to use the triangle sum theorem, properties of equilateral and isosceles triangles, and special angle pairs to determine the unknown measures of angles in three different diagrams. [6:27]
Instructional Video
Khan Academy

Khan Academy: Geometry: Example Involving Isosceles Triangle and Parallel Lines

9th - 10th Standards
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...
Instructional Video
Khan Academy

Khan Academy: Geometry: Challenging Triangle Angle Problem

9th - 10th
Demonstrates how to find the sum of the exterior angles of an irregular pentagon by breaking the pentagon into three triangles and using the triangle sum theorem. [8:37]
Instructional Video
Khan Academy

Khan Academy: Geometry: Another Isosceles Example Problem

9th - 10th
Explains how to use given algebraic expressions for the measures of angles in an isosceles triangle and apply knowledge of the triangle sum theorem and the knowledge that the base angles of an isosceles triangle are congruent to...
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Find a Missing Angle in a Triangle?

9th - 10th
It's important to remember that the interior angles of a triangle always add up to 180 degrees. This tutorial shows you how to put this knowledge into an equation and solve to find a missing measurement. [4:22]
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Find Missing Angles in an Isosceles Triangle?

9th - 10th Standards
Watch this tutorial to learn how identifying a triangle first can be helping in solving for a missing angle measurement. [4:29]
Instructional Video
Virtual Nerd

Virtual Nerd: Why Are the Angles of Equilateral Triangles Always Equal to 60 Degrees?

9th - 10th Standards
In this tutorial, learn how to find the measurements of the interior angles of an equilateral triangle. [5:02]
Instructional Video
Khan Academy

Khan Academy: Triangles: Triangle Angle Example 3

9th - 10th Standards
Explains how to solve for multiple missing angles in a diagram composed of multiple triangles using the triangle sum theorem and other angle relationships.
Instructional Video
Khan Academy

Khan Academy: Sal's Old Angle Videos: Angle Game (Part 2)

9th - 10th Standards
Solving for unknown angle measures using knowledge of different angle relationships and the triangle sum theorem.
Instructional Video
Khan Academy

Khan Academy: Sal's Old Angle Videos: The Angle Game

9th - 10th Standards
Solving for unknown angle measures using knowledge of different angle relationships and the triangle sum theorem.
Instructional Video
Khan Academy

Khan Academy: Triangles: Proof Sum of Measures of Angles in a Triangle Are 180

9th - 10th Standards
Video proving that the sum of the measures of the angles in a triangle are 180.
Instructional Video
Virtual Nerd

Virtual Nerd: Find Missing Angles in an Isosceles Triangle Using Right Triangles

9th - 10th Standards
Discover how identifying your triangle first can be very helpful in solving for a missing interior angle measurement. [3:40]
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Find a Missing Angle in a Right Triangle?

9th - 10th
It's important to first identify what type of triangle you're working with before trying to solve for a missing interior angle measurement. Learn how by watching this tutorial. [3:34]
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Find Missing Angles in a Triangle With Variables?

9th - 10th
This tutorial shows you how to use the Triangle Sum Theorem to find the interior angle measurements of a given triangle. [5:09]
Instructional Video
Khan Academy

Khan Academy: Geometry: Finding More Angles

9th - 10th Standards
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]
Instructional Video
Khan Academy

Khan Academy: Geometry: Triangle Angle Example 2

9th - 10th Standards
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]
Instructional Video
Khan Academy

Khan Academy: Geometry: Triangle Angle Example 1

9th - 10th Standards
Explains how to use the triangle sum theorem to solve for missing angle measures in a triangle. Also addresses the relationship between the measure of an exterior angle of a triangle and the measures of the remote interior angles. This...
Instructional Video
Khan Academy

Khan Academy: Angles (Part 3)

9th - 10th Standards
Identifies and defines the types of angles formed by parallel lines cut by a transversal and the relationship of their measures.