How are angles and sides related? Given several regular convex polygons, the video shows how to calculate the sum of their interior angles. The segment in a playlist on geometry shows how to find the measure of one angle if the polygon...

Use the inside to find the outside. The resource presents two theorems dealing with exterior angles of a triangle. Using the two theorems, the segment from a larger geometry playlist works problems to solve for angle measures.

The measures all add up. The presentation, part of a helpful playlist on geometry, provides the statement of the Triangle Sum Theorem. Using the theorem, the video shows how to find the missing measure of an angle.

Supplement your scholars' knowledge of angles involved with parallel lines. Using the properties of alternate interior angles and linear pairs, the presenter shows interior angles located on the same side of a transversal of parallel...

Is it possible for a pair to be parallel and skew? The resource provides the class opportunities to find out by examining the properties of parallel and skew lines. Part of a playlist on basic geometry, the video includes a brief...

Viewers are presented with seven problems with parallel lines and angle relationships and must use the given information to find the measures of specific angles. To finish, they explain their process in finding the measures in the...

Show your class that finding angle measures is a regular calculation with a resource that provides 12 problems dealing with the measures of angles in regular polygons. Pupils use formulas for the sum of measures of angles in a polygon to...

Using patterns to build a formula is an important mathematical skill. Pupils discover a formula to find the sum of interior angles in a polygon by analyzing a pattern. The additional videos show how to use the formula to find various...

Don't believe everything that you hear — make them prove it! The video shows two methods to prove the Triangle Angle Sum Theorem. The following two videos apply the theorem to finding missing angle measures.

Are you working on finding the missing angles of triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...

Are you working on finding the missing angles in triangles in your class? Consider this video. An instructor uses the triangle sum theorem to create an equation that helps her find the missing angles. She explains each step and writes...

Break down interior and exterior angles with this video. Using a pentagon, a teacher demonstrates how to find the interior and exterior angles of a polygon. She goes on to explain a few of the properties of these angles, writing down all...

The third angle's the charm. Viewers of a short video learn how to find the measure of the missing angle in a triangle. It uses an arithmetic process rather than an algebraic one, so younger learners have no trouble understanding the...

Learn to look at polygons from the right angle. Scholars first use the formula (n - 2) * 180 to determine the sum of the interior angles of a polygon. The video then asks them to consider the sum of the exterior angles.

Oh no, there is a missing angle in a quadrilateral. Where did it go? It didn't go anywhere, it's just missing the value of the angle. So how do you find that missing value? Use a formula of course. Everything in algebra uses a formula....

Squares, pentagons, triangles, polygons. How is it possible to figure out the sum of the interior angles of any of these multi-faceted shapes? There's got to be a formula. Of course there's a formula. That's what algebra is all about,...

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?...

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...

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.

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."

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]

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]

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]

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.