Radford University
How Tall is the Tree?
Pairs or small groups work together to determine the height of a tree using similar triangles. Learners make a judgement which direction to let a tree fall to avoid hitting any structures. They then write letters to the principal...
Mt. San Antonio Collage
Congruent Triangles Applications
Triangles are all about threes, and practicing proving postulates is a great way to get started. The first page of the worksheet provides a brief introduction of the different properties and postulates. The remaining pages contain...
Mathematics Vision Project
Similarity and Right Triangle Trigonometry
Starting with similar triangles and dilation factors, this unit quickly and thoroughly progresses into the world of right triangle features and trigonometric relationships. Presented in easy-to-attack modules with copious application...
Texas Instruments
What's the Trig?
Learners determine the trigonometric relationships within a triangle as they construct a right triangle on the Ti-89. They find the sine, cosine, and tangent of various angles of their triangle construction.
Curated OER
Investigating Segments in a Triangle
Pupils investigate segments in a triangle by constructing a triangle using Cabri Jr. They construct segments within the triangle that lie on the midpoints of the triangle's sides. Learners then compare the slope of base of the triangle...
Curated OER
Investigating Lengths of Segments in a Triangle
Pupils explore the midsegment of a triangle in the geometry lesson. They draw and measure the segment joining the midpoints of the two sides of a triangle and compare its length to the length of the third side of the triangle. The...
That Quiz
That Quiz: Practice Test: Triangles
Test your knowledge on the attributes of triangles. There are eleven levels that may be completed with or without a timer.
Sophia Learning
Sophia: Using Corresponding Parts of Congruent Triangles
This lesson will demonstrate the use of CPCTC in triangle congruency proofs.
CK-12 Foundation
Ck 12: Geometry: Congruent Triangles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students what it means for two triangles to be congruent and how to identify corresponding parts of congruent triangles. Students examine guided...
Khan Academy
Khan Academy: Use Similar & Congruent Triangles
Solve geometry problems with various polygons by using all you know about similarity and congruence.
Math Open Reference
Math Open Reference: Congruent Triangles
A complete reference guide to congruent triangles. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.4 Triangles
Explore and measure a variety of triangles.