Oswego City School District
Regents Exam Prep Center: Pythagorean Theorem
Who was Pythagoras and what is his theorem? Explore this concept and its relationship to the measurement of a right triangle in this test prep lesson plan. The instructional activity includes an interactive worksheet where students...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Triangle Altitudes
Here at the Math Forum, Dr. Math proves the concurrency of the altitudes of a triangle. Links are provided for associated topics.
Other
Antonio Gutierrez: Geometry From the Land of the Incas
Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...
Oswego City School District
Regents Exam Prep Center: Concurrence
Find resources for class instruction on concurrence: a lesson on concurrence of medians, altitudes, angle bisectors, and perpendicular bisectors complete with definitions and example diagrams; a six-question practice quiz; and...
Oswego City School District
Regents Exam Prep Center: Theorems and Postulates for Geometry
Here is a partial list of theorems, postulates, and properties.
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
Oswego City School District
Regents Exam Prep Center: Working With Sets and Venn Diagrams
A collection of activities that help students understand number relationships by using Venn diagrams to solve math problems. Practice problem solving skills in the interactive practice. Then, follow up with a classroom activity using the...
Other
University of Evansville: Encyclopedia Triangle Centers
This site contains a comprehensive study of triangle centers. Seems more for an advanced level. Provides a list of six links to 1114 centers.
US Navy
Naval Historical Center: Exorcizing the Devil's Triangle
Howard L. Rosenberg writes this article about the area known as "The Devil's Triangle" or "The Bermuda Triangle." Besides discussing famous lost ships and airplanes, Rosenberg gives detailed information about the geography of the sea...
Oswego City School District
Regents Exam Prep Center: Reference Angles and Triangles
The mathematics session investigates reference angles and triangles. The tutorial consists of class notes, examples, and practice problems with solutions. The teacher resource includes a worksheet on the construction of skateboarding ramps.
The Dirksen Congressional Center
Congress Link: Lesson Plans
The Dirksen Congressional Center provides abundant lesson plans on all aspects of the US Congress and the US Constitution. All lessons contain time frames, objectives, and links to material, and are built around Bloom's taxonomy.
Oswego City School District
Regents Exam Prep Center: Working on a Rescue Team Lab
Your students are part of the Yellowstone National Park rescue team which has just been dispatched to help located a downed plane. How can they effectively use the Law of Sines and the Law of Cosines to assist them in finding the plane?...
Wolfram Research
Wolfram Math World: Orthocenter
This site from MathWorld provides a diagram of a triangle with its orthocenter labeled. The site details how to find the orthocenter with links to the key terms. The site details many other interesting properties of the triangle...
National Institute of Educational Technologies and Teacher Training (Spain)
Ministerio De Educacion: Veintiocho Cerillas
Remove four matches to the center of the square then repositions the other matches in such a way that the sum of them on each side is 11.
Other
Ctte: Geometer's Sketch Pad Activities
This site offers numerous activities for middle school and high school students to explore using Geometer's Sketch Pad.
CK-12 Foundation
Ck 12: Geometry: Geometric Translations
[Free Registration/Login may be required to access all resource tools.] In this lesson, students learn how to translate a figure. They examine guided notes, review examples, watch instructional videos, and try practice problems.
PBS
Pbs: Mathline: Tessellations Wow! [Pdf]
An integrated geometry lesson on spatial sense in which students identify and use different shapes to create a tessellation. "Through a variety of modalities such as writing, music, art, poetry, and literature, students are introduced to...
Wolfram Research
Wolfram Math World: Circumcenter
MathWorld diagrams a triangle with its circumcenter labeled and details how to find the circumcenter with links to the key terms.