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...

Understand the difference in finding angle measures. A segment of an extensive geometry playlist introduces the formula to find the measure of an angle formed outside of a circle. Using examples, the video shows how to calculate measures...

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...

Supplementary, obtuse, acute, complementary angles. It's good to know what all of these mean, but let's focus on one at a time. Complementary angles always add up to 90 degrees. So if given one angle in a complementary angle problem, the...

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,...

As preparation for the angle game, a geometry video covers the concepts of parallel lines, transversals, slope, opposite angles,, and corresponding angles. It is the third part of a series detailing the rules and laws regarding angles.

What properties of equality also work for congruence? Part of basic geometry playlist, the video relates algebraic properties to their counterparts of congruence. Learners see how the properties mean the same whether with equality or...

A tangent line always finds its place at a 90-degree angle to a radius. Many scholars struggle with the proof of the seemingly simple statement. A brief video demonstrates the reasoning behind the proof before pupils practice applying it...

Here's a special lesson about some special parallelograms. The fifth of seven parts in the Geometry - Quadrilaterals and Polygons unit focuses on the conditions for rectangles, rhombuses, and squares. Young mathematicians use these...

An angle is formed when two rays share a common endpoint. Want to know more about angles? There are a lot of terms in this lesson. You might have to watch it two or even three times to make sure you understand all the terms. I recommend...

Angles are identified by the measurement of their angles. Well, that would make sense. The instructor illustrates four different angles and their names by identifying their degrees. Zero to less than 90 degrees is an acute angle, while...

Skew lines? What? By definition, skew lines are lines on different planes that never intersect. Watch this video and get an explanation along with a visual diagram.

What are supplementary angles? They are two angles that when added together make 180 degrees on a straight angle line. Hard to picture that? Then watch this video and see how the instructor illustrates this on a diagram.

The interior angles of any and ALL triangles adds up to 180 degrees. So if given two of the angle degrees, is it possible to find the value of the third angle? Yes! Use the triangle sum theorem to solve for the missing angle. Watch this...

Using the definition of a trapezoid, the segment within a large playlist on basic geometry explains other properties of trapezoids. The video introduces the special properties held by isosceles trapezoids.

Trapezoids can be tricky! Break down the process of finding the area of a trapezoid with an engaging math video. Learners explore area formula and shown exactly how to plug in information, solve, and simplify. 

Provide pupils with problems on applying properties of parallelograms. The second of seven installments in the Geometry - Quadrilaterals and Polygons unit focuses on parallelograms. Viewers of the instructional video learn about the...

Back with "more energy," Sal begins his explanation of problems 15-18 on page 412 of The Official SAT Study Guide. Problems include angles of equilateral triangles, rectangles, and graphing slopes.

Pupils review the vocabulary, formulas, and postulates from the opening unit in Geometry. Individuals use these to solve a problem set that requires learners to apply algebraic skills along with providing reasons within a proof. Scholars...

Two figures are congruent if they have the same size and shape. Line segments can also be congruent if they are of the same length. Vertical angles created by intersecting lines are always congruent. Polygons that have matching angles...

Finding perimeters and slopes is the focus of this video, which details ways to solve problems 15-17 on the practice SAT. Even students who are confident in their ability to pass the SAT would benefit from this additional review.

Delving into proof that the diagonals of a rhombus are perpendicular to each other, this lecture evaluates the angles and sides of this figure. It would serve as a great test preparation activity.

The final video of the SAT practice series takes students through increasingly complicated algebra and geometry problems, but Sal works steadily through each mathematical process. At the end of the video he tells students that they are...

Problem number 6 on the practice SAT involves solving for a distance on a line, which Sal does in about 2 minutes. His method of efficiently (and correctly) solving problems is an excellent model for students who tend to panic at the...