Curated OER
Proofs Of The Pythagorean Theorem?
Even U.S. President James Garfield had his own proof of the Pythagorean Theorem! Pupils consider three different attempts at a geometric proof of the Pythagorean Theorem. They then select the best proof and write paragraphs detailing...
Curated OER
Tangrams
Students construct tangram pieces. Then they make observations and explore patterns with the pieces.
Curated OER
Similar Polygons
In this similar polygons worksheet, 10th graders solve and complete 20 various types of problems. First, they solve each proportion. Then, students write a ratio expressing the slope of a line through each pair of points. In addition,...
Curated OER
Polygons All Around Us!
Pupils explore the concept of polygon properties. In this polygon properties lesson, students draw polygons with different numbers of sides such as pentagons, octagons, hexagons, etc. Pupils identify different geometric shapes in the...
Curated OER
Tangrams
Young scholars construct the tangram pieces from a square paper by following directions to fold and cut. They make observations on the pieces formed and compare how they are related to each other. They explore patterns and shapes with...
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: Hl Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] This concept introduces the HL Triangle Congruence shortcut in order to prove that two right triangles are congruent. Students work on mastering the skill by watch...
CK-12 Foundation
Ck 12: Geometry: Sss Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] This concept introduces students to the SSS Triangle Congruence Postulate and how to prove that two triangles are congruent given only information about their side...
Other
Nearpod: Triangle Congruence
In this activity, students will prove triangles are congruent using the triangle congruence theorems.
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...
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...
CK-12 Foundation
Ck 12: Geometry: Hl Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two right triangles are congruent with the Hypotenuse-Leg shortcut. Students examine guided notes, review guided practice, watch...
CK-12 Foundation
Ck 12: Geometry: Sss Triangle Congruence
[Free Registration/Login may be required to access all resource tools.] Prove two triangles are congruent with the Side-Side-Side shortcut.
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.
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.
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.
Illustrative Mathematics
Illustrative Mathematics: G Co Are the Triangles Congruent?
In each of the following diagrams, two triangles are shaded. Based on the information given about each diagram, decide whether there is enough information to prove that the two triangles are congruent. Aligns with G-CO.B.
Texas Instruments
Texas Instruments: Congruent Triangles
After students have learned all postulates and theorem to prove triangles congruent, this short quiz can be used to test understanding.
Jim Loy
Jim Loy's Mathematics Page: Congruence of Triangles
Find explanations of the ways to prove triangles are congruent. There is a link for Congruence Of Triangles, Part II to find the proofs of some ways to prove congruence of triangles from other postulates (i.e. Assume SAS prove ASA).
Illustrative Mathematics
Illustrative Mathematics: G Co, G Srt Congruence of Parallelograms
In this task, a student has learned the SSS and SAS congruence tests for triangles and wonders if these tests might work for parallelograms. Aligns with G-CO.C.11 and G-SRT.B.5
Illustrative Mathematics
Illustrative Mathematics: G Gpe, G Co, G Srt Unit Squares and Triangles
In this task, young scholars are shown three unit squares and two line segments connecting two pairs of vertices. They are asked to find the area of a triangle formed by intersecting lines. They can solve it using coordinate geometry or...
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.
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.co Reflections and Isosceles Triangles
This task has students link their intuitive notions of symmetries of a triangle with statements proving that said triangle is unmoved by applying certain rigid transformations. The mechanism through which students do this is via...