Texas Instruments
Texas Instruments: Triangle Sum
This activity is used to discover that the sum of the measures of the triangle angles is constant and to discover ways of proving the theorem listed in the activity.
Texas Instruments
Texas Instruments: Properties of the Centers of a Triangle
Students investigate the sum of the measures of the interior angles of a triangle. This activity explores interior angles, and their relationship with the exterior angles of a triangle [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Classifying a Triangles by Their Angle Measure Using Cabri Jr
This activity uses Cabri Jr to classify triangles according to their angle measure. [Requires Adobe Reader.]
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.
Texas Instruments
Texas Instruments: Angles of a Triangle
In this activity, students will measure angles and investigate the relationships between interior and exterior angles of a triangle. They understand the definition of interior angles, exterior angles, adjacent angles, supplementary...
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.
AAA Math
Aaa Math: Types of Triangles Based on Angles
Students can practice classifying triangles based on angle measurements through a series of self-check exercises and timed learning games.
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...
OER Commons
Oer Commons: Classifying Triangles
For this lesson, students learn to classify triangles by the size of the angles and the measures of the sides. Students will use interactives to explore equilateral, isosceles, scalene, acute, obtuse, and right triangles. Included are...
Louisiana Department of Education
Louisiana Doe: Louisiana Believes: Eureka Math Parent Guide: Angle Measure and Plane Figures
A guide to support parents as they work with their students in angle measure and plane figures.
Mangahigh
Mangahigh: Shape: The Angles Inside a Triangle
Test your knowledge of the missing angle measure.
Khan Academy
Khan Academy: Find Angles in Congruent Triangles
Given two triangles, determine whether they are congruent and use that to find missing angle measures.
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...
Texas Instruments
Texas Instruments: Sum of Remote Interior Angles Equals Exterior Angle
Draw a triangle with exterior angle. Measure the exterior angle and each remote interior angle. Use the Alpha hand to check that the sum of the remote interior angles is always equal to the exterior angle.
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.
Khan Academy
Khan Academy: Determine Similar Triangles: Aa
Given two triangles with some of their angle measures, determine whether the triangles are similar or not.
TeachEngineering
Teach Engineering: The Invisible Radar Triangle
Students learn about radar imaging and its various military and civilian applications that include recognition and detection of human-made targets, and the monitoring of space, deforestation, and oil spills. They use technology tools to...
Maths Challenge
Maths challenge.net: Right Triangle Equal Parts
A geometry proof problem involving a right triangle and finding angles of equal measure.
TeachEngineering
Teach Engineering: You've Got Triangles!
Students learn about trigonometry, geometry and measurements while participating in a hands-on interaction with LEGO MINDSTORMS NXT technology. First they review fundamental geometrical and trigonometric concepts. Then, they estimate the...
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...
CK-12 Foundation
Ck 12: Geometry: Triangle Classification by Angles
[Free Registration/Login may be required to access all resource tools.] Classify different types of triangles by their angles.
CK-12 Foundation
Ck 12: Determination of Unknown Triangle Measures Given Area
[Free Registration/Login may be required to access all resource tools.] Looks at triangle problems where you are given the area and must use trigonometry to find unknown sides or angles.
Khan Academy
Khan Academy: Solve for an Angle in Right Triangles
Given two sides in a right triangle, find one of the acute angles using trigonometry.
Exploratorium
Exploratorium: Ilion High: Build a Clinometer
Instructions for building a clinometer are given on this page. Clinometers can be used to measure the angle of elevation of a right triangle, and in turn find the height of large objects.