CK-12 Foundation
Ck 12: Geometry: Self Similarity
[Free Registration/Login may be required to access all resource tools.] This concept introduces students to self-similarity and presents several common examples of self-similarity.
Khan Academy
Khan Academy: Find Angles in Congruent Triangles
Given two triangles, determine whether they are congruent and use that to find missing angle measures. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
CK-12 Foundation
Ck 12: Geometry: Sas Similarity
[Free Registration/Login may be required to access all resource tools.] Use the SAS Similarity Theorem to determine if triangles are similar.
CK-12 Foundation
Ck 12: Geometry: Parallel Lines and Transversals
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to use the Triangle Proportionality Theorem with multiple parallel lines.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Introduction
This lesson is an introduction to triangles and trigonometry by looking at the history of mapping and specifically, measuring the height of a mountain.
Sonoma State University
Sonoma State University: Parallel Lines and Similar and Congruent Triangles
This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.
TeachEngineering
Teach Engineering: You've Got Triangles!
Students learn about trigonometry, geometry and measurements while participating in a hands-on interaction with LEGO MINDSTORMS NXT technology. First they review fundamental geometrical and trigonometric concepts. Then, they estimate the...
AAA Math
Aaa Math: Geometry
A comprehensive tutorial from AAA Math that contains explanations, interactive practices and challenging games.
CK-12 Foundation
Ck 12: Indirect Measurement
[Free Registration/Login Required] Students use similar triangles to determine the height of the base of a tree house. Click learn more to watch a video and click challenge me to answer a practice question.
CK-12 Foundation
Ck 12: Geometry: Perimeter and Area Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide looks at the definitions and units for perimeter, area, and circumference, and at the perimeter and area of different shapes, including regular...
Alabama Learning Exchange
Alex: How Tall Is the School's Flagpole?
The purpose of this lesson plan is to help learners apply math concepts concerning similar triangles and trigonometric functions to real life situations. The students learn how to take these concepts and use them to find measurements of...
University of Cambridge
University of Cambridge: Maths and Sports: Stadium Sightline
How would you design the seating for an Olympic stadium to give spectators the best view of events? This geometry and modelling activity is designed to be accessible to both GCSE and A-level maths students (Key Stage 4 and Key Stage 5),...
Cuemath
Cuemath: Pythagoras Theorem
In this lesson, you will learn about the Pythagoras theorem, its derivations, and equations followed by solved real-world problems on the Pythagoras theorem triangle and squares.
CK-12 Foundation
Ck 12: Geometry: Parallel Lines and Transversals
[Free Registration/Login may be required to access all resource tools.] Apply the fact that transversals cut parallel lines proportionally.
ClassFlow
Class Flow: Ratio and Proportion Geometry Review
[Free Registration/Login Required] This flipchart is a Jeopardy style review for Ratio and Proportion. Comes form the McDougal Littell Geometry book.
Illustrative Mathematics
Illustrative Mathematics: 8.g, G Gpe, G Srt, G Co Is This a Rectangle?
For this task, students are given four sets of coordinate pairs and are asked to determine if they represent a rectangle. Aligns with 8.G.A, 8.G.B, G-CO.B, G-GPE.B, and G-SRT.B.5.
Texas Instruments
Texas Instruments: The Tangent Ratio
In this activity students explore the tangent ratio. Students construct a right triangle using perpendicular lines, and a line that forms the hypotenuse of the triangle. When students construct the hypotenuse line it is very important...
Sonoma State University
Sonoma State University: Parallel Lines and Similar and Congruent Triangles
This site defines eleven theorems relating to parallel lines and similar and congruent triangles. Links to the theorems and relevant term descriptions are provided.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Geometry Distance of Triangles Using a Protractor
Basic exercises are presented to help students understand the concept of the area of triangles and the angles of a triangle.
Alabama Learning Exchange
Alex: Tan Ii
The Chinese character mark for Tan II (pronounced she-tow-bah) is the second of two lessons to introduce first grade students to geometry using tangrams. This lesson incorporates history, math, and language arts. In this lesson students...
Mangahigh
Mangahigh: Shape: Recognize Congruent Shapes
Determine whether shapes are congruent or similar.
Texas Education Agency
Texas Gateway: Writing Geometric Relationships
Given information in a geometric context, students will be able to use informal arguments to establish facts about the angle sum and exterior angle of triangles, the angles created when parallel lines are cut by a transversal, and the...
Alabama Learning Exchange
Alex: "Tan"
The Chinese character mark formerly known as "Tan" is the first of two lessons to introduce first grade students to geometry using tangrams. This lesson incorporates history, math, and language arts. In this lesson students will be able...
Hunkins Experiments
Hunkin's Experiments:how to Measure the Height of a Tree
Hunkin's Experiments is a group of simple cartoon illustrations of scientific principles. Some would work well in the classroom, but others have little value beyond entertaining students. All of the projects are easy to do. This part...