Houghton Mifflin Harcourt
Holt, Rinehart and Winston: Homework Help Independent Practice: Triangles
Get independent practice working with triangles. Each incorrect response gets a text box explanation and another try. Correct responses are confirmed.
Rice University
Rice University: Geometry Online: Impossible Triangles
This site has an activity that displays several impossible triangles. The rules for triangles are also displayed. The student has to determine which rule has been violated for each impossible triangle.
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
Students explore the nature of triangles and their area. An applet and instructor resources are included. [Requires Java.]
Texas Instruments
Texas Instruments: Dynamic Geometry: Basic Constructions
Students use the Cabri Jr. application to draw triangles and construct perpendicular bisectors on the sides of a triangles. They study the properties of a triangle and understand how the measures of angles of a triangle is always 180...
SEDL
The Timss Mathematics Segment: Geometry
This site explores the area of congruent triangles and how it is a difficult area to understand.
Homeschool Math
Homeschool Math: Triangles
This lesson plan provides students with an opportunity to practice drawing and measuring triangles and angles. It also shows pictures and gives definitions of each type of angle and triangle.
Texas Instruments
Texas Instruments: Surround and Be Found! Triangular Areas, That Is!
In this activity, students use the Geoboard to determine the area of triangles using the surrounding rectangle technique. They also develop and use formulas to determine the area of triangles. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Try Angle?
In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as...
McGraw Hill
Glencoe Mathematics: Online Study Tools: Triangles and Angles
This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of triangles and angles.
Mangahigh
Mangahigh: Shape: The Angles Inside a Triangle
Test your knowledge of the missing angle measure.
Mangahigh
Mangahigh: Shape: Types of Triangle
Test your knowledge of triangles by identifying the different types.
Mangahigh
Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle
Determine that all angles in a triangle equal 180 degrees.
Mangahigh
Mangahigh: Shape: Right Angle in a Semi Circle Rule
Test your knowledge of the measurement of angles in a triangle.
Khan Academy
Khan Academy: Constructing Triangles
Given the lengths of two sides of a triangle, what can we say about the third side? Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] In this lesson students apply the properties of equilateral triangles. Students examine guided notes, review guided practice, watch instructional videos and attempt...
Soft Schools
Soft Schools: Types of Triangles Quiz
The problems on this quiz give descriptions and properties of specific triangles. Students are expected to read the information and identify the triangle that is being described.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Congruent Triangles and Triangle Relationships
Twenty-four problems cover the topics of congruent triangles and triangle relationships in various settings. 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...
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator: Congruent Triangles and Triangle Relationships
Practice using your graphing calculator for demonstrating congruent triangles. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under each problem.
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] This concept will teach students the properties of equilateral triangles and how to apply them to solve problems. Students examine guided notes, review guided...
CK-12 Foundation
Ck 12: Geometry: Triangle Classification Grade 7
[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.
CK-12 Foundation
Ck 12: Comparing Angles and Sides in Triangles
[Free Registration/Login Required] Students explore angles and sides in triangles by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more about the...
CK-12 Foundation
Ck 12: Sss Triangle Congruence
[Free Registration/Login Required] Students will use the interactive lines to determine if the triangles are congruent. Students can click learn more to watch a video and can click challenge me to answer quiz like questions.
CK-12 Foundation
Ck 12: Sas Triangle Congruence
[Free Registration/Login Required] Students are asked to create a triangle that is congruent to the given triangle. Click on learn more to watch a video and challenge me to answer a practice question.