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: Triangle Relationships Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide reviews terminology for triangles, triangle properties, different types of triangles, and interior and exterior angle theorems.
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.
Cuemath
Cuemath: Triangles
Explore everything about triangles. Learn about the different types, important properties, and how to find its area and perimeter. Check out the solved examples and interactive questions for better understanding.
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....
Free Math Help
Free Math Help: Exterior Angle of a Triangle
This tutorial discusses exterior angles of a triangle. Example problems with explanations are included.
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.
Illustrative Mathematics
Illustrative Mathematics: 8.g Find the Angle
In this task, 8th graders have to reason with angles and angle measurements, including the sum of the angles in a triangle, to deduce information from a picture. Includes a GeoGebra worksheet that the teacher can use for demonstration...
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...
Free Math Help
Free Math Help: Angles of a Triangle Sum
The lesson discusses the angle-sum theorem. The resource consists of an explanation and practice problems with solutions.
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.
Cuemath
Cuemath: Obtuse Triangle
In this mini-lesson, learn about obtuse triangles including the obtuse triangle definition, sides, properties, examples, and other fun facts related to it.