Curated OER
Triangle Similarity
In this triangle similarity activity, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles shown are...
Curated OER
Congruent Trianges - Is This Enough Information?
Seventh graders determine whether two triangles are congruent and provide an explanation to why they are not. They apply concepts of measurement of angles and collect evidence of congruent angles in the world.
Curated OER
Toe to Toe Geo
Students study triangles. In this triangle lesson plan, students compare and classify triangles while milling to music. Students will also trade triangles so they can match up with other similar triangles. Triangles are provided.
Curated OER
Proofs with Triangles
In this geometry worksheet, high schoolers prove triangle congruence by making statements with reasons and concluding with the AAS or HL theorem. There are 2 proofs.
Curated OER
Similar Triangles Multiple Choice
In this triangle relationships activity, students identify measurements in similar and congruent triangles. Each problem features a drawing of two or more triangles. Students identify missing measurements. There are 5 multiple choice...
Curated OER
Geometry Practice: G.G. 28 #2: Triangle Congruence
In this triangle congruence worksheet, students use SSS, ASA, AAS and HL to determine the congruence of triangles. They identify the theorem that proves congruence. This three-page worksheet contains 4 multi-step problems. Answers are...
Curated OER
Congruent Triangles
In this geometry worksheet, 10th graders identify the corresponding parts of congruent triangles. The one page worksheet contains four problems. Answers are not provided.
Curated OER
Triangles
In this triangles worksheet, 10th graders solve and complete 7 different problems. First, they list five ways to prove triangles congruent. Then, students name the method proving the triangles congruent in each problem.
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 13 different problems. First, they use the illustrated congruent triangles to show other congruency in each problem. Then, students determine and prove the angle...
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems that include various forms of triangles. First, they name the method for proving each set of triangles congruent using the given information....
Curated OER
Congruent Triangles
In this congruent triangles worksheet, 10th graders solve and complete 10 different problems to determine whether each set of triangles is congruent or not. First, they copy each diagram onto a piece of paper and mark up the paper with...
Curated OER
More Congruent Triangles
In this congruent triangles learning exercise, 10th graders solve 6 various forms of problems that include a proof and a word problem. First, they draw and label triangles and indicate the additional pairs of corresponding parts that...
Curated OER
Triangle Proofs
Tenth graders complete a unit of lessons on congruent triangles and triangle proofs. They observe and participate in teacher-led discussions of examples of the methods to prove that triangles are congruent, and create an original proof.
Curated OER
Congruent Triangles Postulates
Students discover three lettered postulates that prove triangles congruent.
Curated OER
Testing For Congruent Triangles
Students define and discuss congruency and the corresponding parts between congruent triangles. They create a pair of congruent triangles, test for congruency, and complete a worksheet.
Curated OER
Congruent Triangles - Is This Enough Information?
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
National Council of Teachers of Mathematics
Nctm: Illuminations: Proof Without Words: Pythagorean Theorem
Students use this computer applet to visualize the Pythagorean Theorem.
Texas Instruments
Texas Instruments: Triangle Inequality Theorem
In this activity, students will explore the concepts underlying the Triangle Inequality Theorem by comparing side lengths and angle measures of a triangle. They will use an interactive construction to see why this theorem is true.
Texas Instruments
Texas Instruments: Cabri Jr. Getting Started With Triangles
This activity was developed as an introduction to the Cabri Jr. application on the TI-84 calculator. It investigates some basic properties of triangles. [Requires Adobe Reader.]
Varsity Tutors
Varsity Tutors: Hotmath: The Pythagorean Theorem
Twenty problems cover various aspects of the Pythagorean Theorem. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution" button to check each...
Texas Instruments
Texas Instruments: Triangle Properties Assessment
This activity uses Cabri Jr. to assess the students' knowledge of various segments related to triangles: perpendicular bisector, median, angle bisector, midsegment, and altitude.
Texas Instruments
Texas Instruments: Investigating the Triangle Inequality
One property of a triangle is that the sum of the lengths of any two sides must be greater than the length of the third side. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Triangle Inequalities
This activity will help students visualize the properties of triangles stated in the theorems. By dragging the vertices, the students can see that the properties hold regardless of the size of the triangles and which sides are the...
Khan Academy
Khan Academy: Finding Angle Measures Using Triangles
Use your knowledge of angles to find missing angle measures in various complex situations. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.