Lesson 1: 4-1: Angles of Triangles

1. Which angle measure(s) in a triangle can be found using given information?
2. Which angle measure(s) in a triangle cannot be found until you find another missing angle measure?

Auxiliary Line
Exterior Angle
Remote Interior Angles
Corollary

G.CO.10
Prove theorems about triangles.

https://docs.google.com/document/d/1Wi6oBP9pbwdBW1CPr4x4vVBOYkSXVKTdszWiPd1Ccm4/copy?usp=sharing

The Triangle Angle-Sum Theorem states that the sum of the measures of the interior angles of a triangle is always 180. The Triangle Angle-Sum Theorem is used to prove other theorems about angle relationships. Each angle of a triangle has an exterior angle, which is formed by one side of the triangle and the extension of another side.

Each year, NASA sponsors the RASC-AL Exploration Robo-Ops Competition in which students design and build a robot. One test of a robot's movements is to program it to move in a triangular path. The sum of the measures of the pivot angles through which the robot must turn will always be the same.

Students approaching grade level can be given practice problems in small groups to work with other students or directly with the teacher.
Students beyond grade level can make deeper connections by looking at the sum of the measures of the angles in other polygons and that connection to the number of sides in the polygon.

Formative Assessment

Textbook in class

Access online textbook and resources through class link.