Curated OER
How Do You Find the Sum of the Interior Angles of a Polygon?
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,...
Khan Academy
Angles (Part 3), Angles and Intersecting Lines, Geometry
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.
Brightstorm
Parallel and Skew Lines
Parallel lines are often incorrectly defined as lines that do not intersect. The instructor in a concept video explains the difference between parallel and skew lines. He also refers to the correct notation and symbols during the...
Curated OER
What are Acute, Obtuse, Right, and Straight Angles?
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...
Curated OER
What is an Angle?
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...
Curated OER
What are Skew Lines?
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.
CK-12 Foundation
Angles Outside a Circle: Lesson
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...
Curated OER
How Do You Find a Missing Angle in a Triangle?
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...
Curated OER
What are Supplementary Angles?
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.
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?...
Flipped Math
Parallel Lines and Triangles
Triangles bring sums to geometry. The lesson presents two theorems dealing with the angles of a triangle. Pupils learn about the Triangle Sum Theorem and the Exterior Angle Theorem, and then apply the theorems to create equations and...
Brightstorm
Three Undefined Terms: Point, Line, and Plane
Defining the undefined is the goal of this video. The instructor explains the important features of a point, line, and plane and how they work together. He also addresses the correct ways to name each and describes the correct notation —...
Socratica
Parallel Lines and Transversals
Eight is the lucky number of angles when a line crosses two parallel lines. Scholars watch a concise video in the Socratica Geometry series to learn about angles made by parallel lines and a transversal. Using corresponding and vertical...
Flipped Math
Unit 1 Review: Tools for Geometry
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...
Khan Academy
SAT Prep: Test 1 Section 6 Part 5
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.
Corbett Maths
Angles: Straight Line
Supplement your geometry work with a straight-to-the-point video. A two-minute video reviews how to find the missing angle measure of a pair of supplementary angles given one of the measures. It works through a few examples of the...
Curated OER
What Does Congruent Mean?
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...
Khan Academy
Rhombus Diagonals, Quadrilaterals, Geometry
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.
Khan Academy
SAT Prep: Test 8 Section 8 Part 3
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...
Khan Academy
SAT Prep: Test 3 Section 2 Part 2
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...
Curated OER
What is a Point?
A point is an exact location in space. This tutorial defines the concept of a point as it occurs in graphing, geometry, and algebra. A variety of examples are used to show how important points are and where they'll be seen in the world...
Curated OER
What is a Plane?
It's a bird, it's a plane, it's Superman. No, it's really a plane. A plane is named by identifying three points with the exception that they do not form a straight line. A plane can also be identified by a single letter naming it. The...
Curated OER
What Does Congruent Mean?
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...
CK-12 Foundation
Linear Pairs: Lesson
Place angles in a line. Part of a playlist on basic geometry, an informative video teaches pupils the definition of a linear pair and how to identify them. Using their properties, the resource demonstrates how to solve problems involving...