Texas Instruments
Texas Instruments: Angle Sum in Triangles Proof: Rotation and a Parallel Line
This investigation uses Cabri Jr. and a cleaver rotation of a triangle to "prove" that the angles in a triangle add up to 180. This could be used to reinforce triangles and paralled lines as well as introduce the concept of rotating an...
Government of Alberta
Learn Alberta: Math Interactives: Exploring Angles Within a Triangle
This multimedia Learn Alberta math resource looks at angles of a triangle in the context of building bikes and choosing bike sizes. The accompanying interactive component lets students explore build different sized triangles while...
CK-12 Foundation
Ck 12: Elem Math: Determining the Unknown Angle in a Triangle
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on how to determine a missing angle in a triangle.
Texas Instruments
Texas Instruments: Sum of Interior Angles in a Triangle With Cabri Jr.
Students will discover the sum of the interior angles in a triangle using the Cabri Jr. Application.
Texas Instruments
Texas Instruments: Angles of a Triangle
In this activity, students investigate the sum of the measures of the interior angles of a triangle. They will explore interior angles, and their relationship with the exterior angles of a triangle.
Mangahigh
Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle
Determine that all angles in a triangle equal 180 degrees.
Oswego City School District
Regents Exam Prep Center: Angles and Triangles
On this site a viewer can learn about the different types of triangles, and categorized by either angles or sides. Tutorials are also included for interior and exterior angles of triangles. A teacher resource page includes a lesson plan...
CK-12 Foundation
Ck 12: Geometry: Comparing Angles and Sides in Triangles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the relationship between opposite angles and sides in triangles and how to use this relationship to compare triangles. students examine...
CK-12 Foundation
Ck 12: Geometry: Triangle Sum Theorem Grade 8
[Free Registration/Login may be required to access all resource tools.] Finding and understanding the angle measures of triangles.
CK-12 Foundation
Ck 12: Geometry: Triangle Sum Theorem Grade 7
[Free Registration/Login may be required to access all resource tools.] Recognize the sum of the interior angles of a triangle as 180 degrees.
CK-12 Foundation
Ck 12: Geometry: Exterior Angles Theorems
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the sum of exterior angles for any polygon and the relationship between exterior angles and remote interior angles in a triangle....
Texas Instruments
Texas Instruments: Extension: Parallel Lines and the Sum of the Angles
Students construct a line parallel to the base of a triangle and measure the angles formed. They use the construction to prove that the sum of the measures of the interior angles of a triangle is 180 degrees.
AAA Math
Aaa Math: Finding the Third Angle of a Triangle
Finding the third angle of a triangle becomes easier by the explanation and examples presented.
Varsity Tutors
Varsity Tutors: Hotmath: Algebra Review: Angle Sum Theorem
Find a quick, concise explanation of the Angle Sum Theorem. A step by step explanation of the proof is included to help you understand the theorem.
CK-12 Foundation
Ck 12: Geometry: Triangle Sum Theorem Grades 8 10
[Free Registration/Login may be required to access all resource tools.] Recognize the sum of the interior angles of a triangle as 180 degrees.
CK-12 Foundation
Ck 12: Triangle Sum Theorem
[Free Registration/Login Required] Students explore the concept of the triangle sum theorem by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more...
CK-12 Foundation
Ck 12: Geometry: Angle Measures in Given Triangles
[Free Registration/Login may be required to access all resource tools.] Find the degree measure of an unknown angle in given triangles.
CK-12 Foundation
Ck 12: Triangle Sum Theorem
[Free Registration/Login Required] Students explore the concept of the triangle sum theorem by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more...
CK-12 Foundation
Ck 12: Elem Math: Determine Unknown Angles: Isosceles, Scalene, Right Triangles
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on finding the missing angles in triangles.
CK-12 Foundation
Ck 12: Geometry: Triangle Sum Theorem Grades 9 10
[Free Registration/Login may be required to access all resource tools.] This concept teaches students the Triangle Sum Theorem, and how to use it.
Khan Academy
Khan Academy: Triangle Angles Review
Reviews the rule that the interior angles of a triangle always add up to 180 degrees. Includes three practice problems.
Walter Fendt
Walter Fendt: Sum of Angles in a Triangle
A short interactive activity to show that the sum of the angles of a triangle is 180 degrees.
Khan Academy
Khan Academy: Find Angles in Triangles
Find missing angle measures using the properties of triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.
Texas Instruments
Texas Instruments: Measuring Angles in a Triangle
In this activity, students learn about the sum of the angles in a triangle. They understand triangles and their interior angles.