Texas Instruments
Texas Instruments: Investigating the Angle Sum Theorem of Polygons
This activity will allow students to use Cabri Jr. to find the sum of the measures of interior angles of convex polygons and visually see how the Interior Angle Sum Theorem works.
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.
Texas Education Agency
Texas Gateway: Geometric Properties of Angle Relationships in Polygons
Given numerical and/or geometric patterns that represent geometric properties of angle relationships in polygons, the student will investigate patterns to make conjectures about interior and exterior angles of polygons.
Texas Instruments
Texas Instruments: Exterior and Interior Angle Theorem
In this activity, students investigate the relationship between the exterior angle of a triangle and its remote interior angles. They study the Triangle Sum Theorem and the Exterior Angle 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: 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.
Texas Instruments
Texas Instruments: Measuring Polygons an Introduction to Cabri Jr.
This activity is designed as an introduction to using the Carbri Jr. application on the TI-83+/84+ calculators. Students are guided through the menu system and are shown how to draw triangles, quadrilaterals and and a pentagon. Perimeter...
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....
CK-12 Foundation
Ck 12: Geometry: Exterior Angles Theorems
[Free Registration/Login may be required to access all resource tools.] In this lesson students apply the Exterior Angles Theorems. Students examine guided notes, review guided practice, watch instructional videos and attempt practice...
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.
Texas Education Agency
Texas Gateway: Making Conjectures About Other Polygons
Given information about the properties of polygons, students will verify theorems about the relationships, including the sum of interior angles, and apply these relationships to solve problems.
Khan Academy
Khan Academy: Angles of a Polygon
Find the sum of interior angles of different polygons.
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.
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.
Texas Education Agency
Texas Gateway: Making and Verifying Conjectures About Triangles
Given examples of triangles and their component parts, the student will use explorations and concrete models to verify and apply the and find the sum of interior angles.