Curated OER
Geo Jammin' - Day 2, Lesson 5: Eeny, Meeny, Miney, Mo
Young scholars, in groups, use song lyrics and math to descrie two and three dimensional shapes.
Texas Instruments
Texas Instruments: Centers of a Triangle
The centroid, circumcenter, orthocenter, and incenter are the four classic centers of a triangle that are studied in geometry. In this activity, you will construct these center points and discover their properties. [Requires Adobe Reader.]
Cuemath
Cuemath: Median of a Triangle
This lesson explores the equation of the median of a triangle formula, sum of medians of a triangle, altitude of a triangle, median of equilateral triangle formula, and median of a triangle definition while discovering the interesting...
Oswego City School District
Regents Exam Prep Center: Mid Segment of a Triangle
Three resources to help you plan instruction on the mid-segment of a triangle: a lesson with definition, properties, and examples of a mid-segment of a triangle; a seven-question quiz through which students can practice working with...
Texas Instruments
Texas Instruments: Properties of the Centers of a Triangle
Students investigate the sum of the measures of the interior angles of a triangle. This activity explores interior angles, and their relationship with the exterior angles of a triangle [Requires Adobe Reader.]
Other
Center for Technology and Teacher Education:centers of Triangles Lesson Part Two
This is the second of two consecutive lesson plans concerning the centers of a triangle. The lesson requires the use of Geometer's Sketch Pad. The lesson contains real world applications of some of the concurrent points of a triangle.
Other
Center for Technology and Teacher Education:centers of Triangles Lesson Part One
This is the first of two consecutive lesson plans concerning the centers of a triangle. The instructional activity requires the use of Geometer's Sketch Pad. The instructional activity contains real world applications of some of the...
Oswego City School District
Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig
How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...
Math Open Reference
Math Open Reference: Centroid of a Triangle
A complete reference guide to the centroid of a triangle. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Centroid: Center of Gravity
At this site you will find am online discussion about the centroid of a triangle. The page begins with a discussion of observations leading to the centroid of a triangle. Dr. Math explains the correct findings as well as the errors made...
Oswego City School District
Regents Exam Prep Center: Special Right Triangles 45, 45, 90
This Oswego City School District Regents Exam Prep tutorial shows two special formulas that are used to determined the measures of the legs of a 45-45-90 triangles. If you can't remember the formula, the tutorial gives you tips on other...
Texas Instruments
Texas Instruments: Inscribing a Circle in a Triangle
In this activity, students bisect the angles of a triangle and find the incenter of the triangle. They find the distance from the incenter to the side of the triangle and use it as radius. With the incenter as the center, they inscribe a...
Texas Instruments
Texas Instruments: Circumscribing a Circle About a Triangle
In this activity, students use the distance of the circumcenter of a triangle to each vertex of the triangle as the radius and draw a circle using the circumcenter as the center.
Wolfram Research
Wolfram Math World: Triangle Centroid
This site from MathWorld gives a diagram of a triangle with its centroid labeled. The site details how to find the centroid with links to the key terms. The site details many other interesting properties of the triangle centroid.
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
Oswego City School District
Regents Exam Prep Center: Angles and Triangles
On this site a viewer can learn about the different types of triangles, and categorized by either angles or sides. Tutorials are also included for interior and exterior angles of triangles. A teacher resource page includes a lesson plan...
Oswego City School District
Regents Exam Prep Center: Special Right Triangles
A collection of lessons, practice activities, and a teacher resource that will aid your exploration and understanding of special right triangles.
Oswego City School District
Regents Exam Prep Center: Law of Sines and Law of Cosines
This tutorial examines the law of sines and the law of cosines. Includes class notes, examples, and a variety of practice problems with solutions. The teacher resource consists of a lab that utilizes the law of sines and the law of cosines.
Oswego City School District
Regents Exam Prep Center: Isosceles Triangle Theorem
Material to supplement instruction on isosceles triangles: a lesson with related theorems and examples; an online practice quiz for students to take and check their answers; and guidelines for proving the isosceles triangle theorem.
Math Open Reference
Math Open Reference: Polygons
Get the definition and properties of a polygon. Then explore such topics as: 1) types of polygon 2) area 3) Perimeter 4) angles associated with polygons and 5) names of polygons.
Oswego City School District
Regents Exam Prep Center: Organizing and Venn Diagrams With Congruent Triangles
As a resource for teachers, an activity of how to connect Venn Diagrams with the five methods of proving triangles congruent - SSS, SAS, ASA, AAS, HL - is explained.
Oswego City School District
Regents Exam Prep Center: Similarity of Triangles
Discover the world of "similarity" in this test prep tutorial on similar triangles. Detailed explanation of concept with examples, challenging interactive practice, and a classroom activity that integrates math and science.
Oswego City School District
Regents Exam Prep Center: Mean Proportional in a Right Triangle
Material to supplement classroom instruction on mean proportional in a right triangle: a lesson with a definition of "mean proportional" as well as theorems with examples; an online multiple-choice quiz with answers; and guidelines for...
Beacon Learning Center
Beacon Learning Center: Anglemania!
Students explore four types of angles in this interactive web lesson.