Corbett Maths
Rotational Symmetry
Turn to the resource to discover rotational symmetry. Viewers of an informative video first learn the definition of rotational symmetry. They then see how to identify the order of rotational symmetry for a figure.
Khan Academy
Khan Academy: Geometry: Rhombus Diagonals
Demonstrates how to prove that the diagonals of a rhombus are perpendicular bisectors of each other based on knowledge of triangle congruency postulates and properties of altitudes. [4:38]
Khan Academy
Khan Academy: Geometry: Quadrilateral Properties
This video tutorial [5:07] demonstrates how to use the basic properties of parallelograms, rectangles, squares, rhombi, and trapezoids to determine what are the possible ways to name a given geometric shape.
Khan Academy
Khan Academy: Geometry: Proof Rhombus Diagonals Are Perpendicular Bisectors
Demonstrates how to prove that the diagonals of a rhombus are perpendicular bisectors of each other based on knowledge of properties of parallelogram diagonals, triangle congruency, and supplementary angles. [4:04]
Khan Academy
Khan Academy: Quadrilateral Overview
This video tutorial [8:24] defines what a quadrilateral is and identifies and defines concave quadrilaterals, convex quadrilaterals, trapezoids, parallelgrams, rectangles, rhombi, and squares.
Khan Academy
Khan Academy: Geometry: Congruent Triangle Proof Example
Demonstrates how to use triangle congruency to prove that a given point is the midpoint of a given line segment. The proof is written in the form of a two-column proof. Practice problems available. [5:46]
Khan Academy
Khan Academy: Geometry: Congruent Triangle Example 2
Demonstrates how to use triangle congruency to prove that corresponding sides of congruent triangles are congruent and then identifies other congruent parts in the overlapping triangle diagram. The proof is written in the form of a...
Virtual Nerd
Virtual Nerd: What Is a Triangle?
This tutorial explains triangles and their different types. [5:58]
Virtual Nerd
Virtual Nerd: How Do You Classify Triangles?
If you know what kind of triangle you're looking at, it's much easier to figure out how to solve for various sides and angles. Use this tutorial to practice classifying triangles. [7:15]
Virtual Nerd
Virtual Nerd: How Do You Find Missing Angles in an Isosceles Triangle?
Watch this tutorial to learn how identifying a triangle first can be helping in solving for a missing angle measurement. [4:29]
Virtual Nerd
Virtual Nerd: What Are Equilateral, Isosceles, and Scalene Triangles?
Watch this tutorial to learn about some of the different kinds of triangles. [5:33]
Virtual Nerd
Virtual Nerd: What Is a Rectangle?
Tutorial provides an introduction to rectangles and explains their special properties. [5:56]
Virtual Nerd
Virtual Nerd: What Is a Parallelogram?
Video tutorial takes a look at parallelograms and explores what kinds of quadrilaterals can also be called parallelograms. [7:17]
Virtual Nerd
Virtual Nerd: What Is a Trapezoid?
This tutorial introduces trapezoids and takes a look at the special properties needed for a quadrilateral to be called a trapezoid. [5:27]
Virtual Nerd
Virtual Nerd: What Is a Quadrilateral?
Watch this tutorial to learn about quadrilaterals and their special types. [4:52]
Virtual Nerd
Virtual Nerd: What Is a Square?
Video tutorial explores squares and explains their special properties. [5:59]
Virtual Nerd
Virtual Nerd: What Is a Rhombus?
This tutorial introduces you to the rhombus and explains its special properties. [5:15]
Khan Academy
Khan Academy: Proof Rhombus Diagonals Are Perpendicular Bisectors
Proving that the diagonals of a rhombus are perpendicular.
Khan Academy
Khan Academy: Sss to Show a Radius Is Perpendicular to a Chord That It Bisects
More on the difference between a theorem and axiom. Proving a cool result using SSS.
Khan Academy
Khan Academy: Quadrilaterals: Quadrilateral Overview
This video identifies and defines concave quadrilaterals, convex quadrilaterals, trapezoids, parallelgrams, rectangles, rhombi, and squares.
Khan Academy
Khan Academy: Quadrilaterals: Whether a Special Quadrilateral Can Exist
A video proving whether a special quadrilateral can exist.
Sophia Learning
Sophia: Notation for Congruent Parts
Explore the notation used to represent congruent sides and angles in a triangle. Take a quiz to assess learning.
Sophia Learning
Sophia: Properties of Equilateral Triangle and Takin' It 2 the Streets
Use examples to solve for the angles of equilateral triangles in a PowerPoint presentation. Includes video. [4:18]
Virtual Nerd
Virtual Nerd: Find Missing Angles in an Isosceles Triangle Using Right Triangles
Discover how identifying your triangle first can be very helpful in solving for a missing interior angle measurement. [3:40]