CK-12 Foundation
Congruent Triangles: Lesson
Given two congruent triangles, the resource provides the definition of congruent triangles and marks the corresponding parts. The portion of a basic geometry playlist shows the triangles are congruent by moving one on top of the other...
CK-12 Foundation
Area of Composite Shapes: Lesson
To find the whole, add and subtract the pieces. A portion of a massive geometry playlist shows how to approach finding the area of a composite figure. The resource works with a couple different composite shapes to find their areas.
Curated OER
Types of Polygons - Geometry Help
If it has three sides it's a triangle! Learn about the different types of polygons and how they are classified by the number of sides they have. This clip clearly defines each type of polygon, but fails to show examples.
Corbett Maths
Area of a Shape on a Grid
What does a grid have to do with area? Well, just about everything! Learners view composite shapes on a grid and watch as the video instructor finds their areas. The examples use shapes composed of rectangles and triangles. Scholars...
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...
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...
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,...
Curated OER
What is a Pyramid?
One base, triangular sides, and defined polygons are all parts of what make up a pyramid. Check out this video and see the instructor draw pictures of a variety of pyramids. She identifies the specific parts and gives them names based on...
CK-12 Foundation
Area and Perimeter of Rhombuses and Kites: Lesson
Flip the triangles up and create a parallelogram. Using the idea of transformations, the video develops the area formula for rhombi and kites. The segment of an extensive geometry playlist uses the formula to find the areas of different...
TED-Ed
Why Are Manhole Covers Round?
Discover the peculiar geometric property of the curve of constant width, the Reuleaux triangle, and their intriguing connection to manhole covers with yet another fascinating TED-Ed video.
Curated OER
What is the Formula for the Volume of a Prism?
Is prism just another mathematical term for a solid? It must be since this lesson is about volume. The teacher illustrates and explains how to find the volume of a rectangular prism and also how to find the volume of a triangular prism....
Curated OER
What is a Polygon?
What makes a figure a polygon? Does it have three or more sides? Is it a closed figure? If the answer is yes to both of those questions then it's a polygon. But wait! Some of these polygons have special names based on the number of sides...
Curated OER
How Do You Find a Missing Angle in a Quadrilateral?
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....
Mathed Up!
Mixed Transformations
Viewers learn how to identify and perform a variety of transformations with a video that provides seven items on transformations. Pupils demonstrate their understanding of dilations, reflections, rotations, and translations. The video...
Mathed Up!
Translations
Introduce translations as transformations that move figures in horizontal and vertical distances with a video that shows how to translate the figures. A second video covers how to determine the translation that has occurred. Pupils...
Curated OER
Circles: Radius, Diameter and Circumference
Fascinating discussion regarding the origin of Pi accompanies a detailed explanation of how to find the circumference of a circle. Since this is the first installment in a series on circles, the concept of circumference is separated into...
Sophia Learning
Sophia: Quadrilaterals and Triangles
In this video tutorial [4:17], students will explore the attributes that triangles and quadrilaterals have and how they share certain properties. Assess learning with a quiz.
CK-12 Foundation
Ck 12: Elem Math: Overview of Rectangles Squares Circles and Triangles
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on various two dimensional shapes including rectangles, squares, circles and triangles.
CK-12 Foundation
Ck 12: Elem Math: Overview of Rectangles Squares Circles and Triangles
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on the properties of rectangles, squares, circles and triangles.
PBS
Pbs Learning Media: Peg + Cat: Geometry Collection
This collection includes 16 Peg + Cat video clips about geometry including 2-D and 3-D shapes.
Khan Academy
Khan Academy: Triangle Inequality Theorem
Explains the Triangle Inequality Theorem, which states that the sum of two sides of a triangle is always more than the length of the third side. [5:52]
Loyola University Chicago
Math Flix: Polyhedra Nets 1
This QuickTime movie provides an opportunity to identify Polyhedra using Nets. As you watch and listen to the teacher and student interact it helps clarify the thinking behind applying this concept.
Loyola University Chicago
Math Flix: Similar Figures: Cross Multiplication
This QuickTime movie provides an opportunity to develop the basic geometric term, similar, by using cross multiplication to see if figures are similar. As you watch and listen to the teacher and student interact it helps clarify the...