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.
Texas Instruments
Texas Instruments: Investigate Triangles and Congruence
Students can use the TI-84 Plus family with Cabri Jr. to prove triangle congruence with SSA.
Texas Education Agency
Texas Gateway: Using Logical Reasoning to Prove Conjectures About Circles
Given conjectures about circles, the student will use deductive reasoning and counterexamples to prove or disprove the conjectures.
CK-12 Foundation
Ck 12: Geometry: Asa and Aas Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two triangles are congruent with the Angle-Side-Angle and Angle-Angle-Side shortcuts. Students examine guided notes, review guided...
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Triangles Congruence
This lesson focuses on triangle congruence; it shows the ways to prove that triangles are congruent.
CK-12 Foundation
Ck 12: Geometry: Sas Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] Prove two triangles are congruent with the Side-Angle-Side shortcut.
CK-12 Foundation
Ck 12: Geometry: Sas Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] This concept introduces students to the SAS Triangle Postulate and how to prove that two triangles are congruent given only information about two pairs of sides and...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Congruence and Triangles
This site gives a very thorough explanation of how to tell if two triangles are congruent. Dr. Math explains why SSS, SAS, ASA determine that two triangles are congruent. The Dr. gives a few exercises for the reader to try then gives the...
Illustrative Mathematics
Illustrative Mathematics: G Srt Joining Two Midpoints of Sides of a Triangle
In this task, students must prove that angles and triangles are congruent and that a parallel line passes through the midpoints of two sides of the larger triangle. Aligns with G-SRT.B.4.
Khan Academy
Khan Academy: Proofs With Transformations
Explore different ways of proving some theorems about lines and angles. Some transformations are used.
Illustrative Mathematics
Illustrative Mathematics: G Gpe a Midpoint Miracle
In this task, students are asked to draw a quadrilateral so that no two sides are congruent, no two angles are congruent, and no two sides are parallel. The task gives students the opportunity to prove that if we join the midpoints of a...
Illustrative Mathematics
Illustrative Mathematics: 8.g Tile Patterns I: Octagons and Squares
Eighth graders are presented with a tile pattern showing an apparent square surrounded by four octagons. They are asked to answer a question about congruency and angle measurements, as well as prove that the interior shape is really a...
Wolfram Research
Wolfram Math World: Rectangle
MathWorld provides the definition of a rectangle and the area formula of a rectangle.