Curated OER
How Do You Find the Measures of Exterior Angles of a Polygon if You Know the Interior Angles?
What are the exterior angles of a polygon? Polygons have exterior angles? How? Oh, extend all the lines, and find the value of each of the supplementary angles. No problem as long as one knows what supplementary angles means. Not sure?...
Curated OER
How Do You Find Missing Angles in a Transversal Diagram?
Parallel lines with a transversal and one given value, find the value of the other seven angles. There are many geometric terms about angles and lines to know the meaning of and understand their relationship to each other. Understanding...
Virtual Nerd
What is the Triangle Sum Theorem?
If you add the value of the three interior angles in a triangle will it equal 180 degrees? Yes it will. The instructor illustrates and proves the Triangle Sum Theorem. Follow closely as she explains her proof.
Sophia Learning
Sophia: Equilateral Triangle Interior Angles Practice Problems: Lesson 1
This lesson will provide practice problems that involve solving for unknown angle and side measures of equilateral triangles. It is 1 of 5 in the series titled "Equilateral Triangle Interior Angles Practice Problems."
Khan Academy
Khan Academy: Geometry: Ca Geometry: Exterior Angles
Demonstrates solutions to problems #41-45 of California Geometry released state test questions. Problems address finding volumes of rectangular prisms, exterior angles, interior angle sum, and exterior angle sum. [10:53]
Khan Academy
Khan Academy: Geometry: Ca Geometry: Deducing Angle Measures
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]
Khan Academy
Khan Academy: Geometry: Sum of Interior Angles of a Polygon
Demonstrates how to generalize the formula for finding the interior angle sum of a polygon by noticing how many non-overlapping triangles a polygon can be broken into. Practice problems available. [9:10]
Sophia Learning
Sophia: Consecutive Interior Angles Converse
This video tutorial describes and provides an example for proving two lines are parallel with the converse of consecutive-interior angles theorem. Students can check their understanding with an assessment.
Sophia Learning
Sophia: Coordinate Geometry of Rectangles
Coordinate geometry of rectangles is investigated in this video lesson. The tutorial demonstrates how to use the midpoint, distance, and slope formulas to determine if a quadrilateral is a rectangle on a coordinate plane. [17:26]
Sophia Learning
Sophia: Interior and Exterior Angles of Polygons
Interior and exterior angles of polygons are investigated in this geometry resource. Definitions and video lessons are included.
Sophia Learning
Sophia: Interior Angles
Explore the interior angles of polygons and the degree of each angle as well as the total degree of the entire polygon. Assess learning with a quiz.
Sophia Learning
Sophia: Introduction to Triangle Similarity
Similar Triangles are explored in this video lesson. Students can check their understanding with an assessment. [5:51]
Sophia Learning
Sophia: Quadrilaterals and Triangles
This video lesson [4:55] describes the characteristics that quadrilaterals and triangles have in common. Students can check their understanding with an assessment.
Sophia Learning
Sophia: Triangle Interior Angles Practice
Determine the value of a variable when solving for the interior angles of a triangle. Check understanding with a quiz.
Sophia Learning
Sophia: Angles of a Triangle
This video tutorial demonstrates how to find the interior and exterior angles of a triangle.
Sophia Learning
Sophia: Special Right Triangles
Special right triangles are explored in this video tutorial. The lesson provides four videos that explain the side ratios for 45-45-90 and 30-60-90 triangles along with real-world examples involving each type of triangle.
Virtual Nerd
Virtual Nerd: How Do You Find the Sum of the Interior Angles of a Polygon?
If you know the number of sides of a polygon, you can figure out the sum of the interior angles. Take a look at this tutorial to learn how. [6:00]
Virtual Nerd
Virtual Nerd: How Do You Find Missing Angles in a Triangle With Variables?
This tutorial shows you how to use the Triangle Sum Theorem to find the interior angle measurements of a given triangle. [5:09]
Virtual Nerd
Virtual Nerd: How Do You Find a Missing Angle in a Quadrilateral?
This tutorial demonstrates how to create an equation and solve it to find the missing measurements in a quadrilateral. [4:13]
Khan Academy
Khan Academy: Triangle Angle Properties: Sum of Interior Angles of a Polygon
Students explore the interior angles of a polygon by explanding on the concept that a triangle has 180 degrees and developing a formula for all polygons.
Sophia Learning
Sophia: Equilateral Triangle Interior Angles Practice Problems: Lesson 4
This lesson will provide practice problems that involve solving for unknown angle and side measures of equilateral triangles. It is 4 of 5 in the series titled "Equilateral Triangle Interior Angles Practice Problems."
Sophia Learning
Sophia: Triangle Interior Angles Practice: Lesson 4
This lesson provides practice problems that involve the sum of the interior angles of triangles. It is 4 of 6 in the series titled "Triangle Interior Angles Practice."
Sophia Learning
Sophia: Triangle Interior Angles Practice: Lesson 6
This lesson provides practice problems that involve the sum of the interior angles of triangles. It is 6 of 6 in the series titled "Triangle Interior Angles Practice."
Sophia Learning
Sophia: Using Triangles to Find the Sum of Interior Angles: Lesson 2
This lesson demonstrates how to use triangles to determine the sum of the interior angles of a polygon. It is 2 of 5 in the series titled "Using Triangles to Find the Sum of Interior Angles."