12 Components
Big Ideas
Formative Assessment Lesson
End of Unit Assessments
Browse Components
Big Ideas
Formative Assessment Lesson
End of Unit Assessments
Big Idea:

### Angle relationships determine properties about triangles.

1 week

Evidence of Understanding

• explore and prove qualities about the interior and exterior angles of any triangle
• use examples and nonexamples to determine when an angle within a triangle can be classified as interior or exterior
• analyze examples to justify that interior angles always add up to 180°  and the exterior angles add up to 360°  and attempt to create counterexamples
• use tools to draw triangles and measure angles, and explain the impact of human error in this process
• describe and classify triangles based on their angle measures (right, acute, obtuse)
• describe how the relationships between interior angles of a triangle impact its corresponding side lengths and classification (equilateral, isosceles, scalene)
• use deductive reasoning to prove that, for any triangle, the three interior angles add up to 180°  and the three exterior angles add up to 360°
• draw or construct auxiliary lines and apply the properties of parallel lines
• find the values of missing interior angles of a triangle

• identify and describe relationships between the interior and exterior angles of a triangle
• analyze examples to justify thatthe exterior angle is always equal to the sum of the two remote angles  and attempt to create counterexamples
• use deductive reasoning to prove that the exterior angle is always equal to the sum of the two remote angles
• describe the reflexive and transitive properties when using triangle sum and linear pair in the proof
• find the measure of missing interior or exterior angles

Develop conceptual understanding:

Interior, exterior, triangle, isosceles, equilateral, scalene, right, acute, obtuse, example, nonexample, interior angles of a triangle, exterior angles of a triangle, remote interior angles (non-adjacent interior angles), auxiliary line, counterexample

Supporting terms to communicate:

side lengths, angle measure, congruent, construct, supplementary, complementary, congruent, straight angles, reflexive property, transitive property, substitute, adjacent
Core Resource

A core resource supports multiple days of instruction.

• Analyzing Angles
This incomplete core resource supports students in developing relationships between the measure of the interior, exterior, and remote angles of a triangle.
Resource:
Analyzing Angles

This incomplete core resource supports students in developing relationships between the measure of the interior, exterior, and remote angles of a triangle.

All Resources From:
• Unit 2

Instructional Routine: Sharing Skepticism

The primary goal of this instructional routine is to support students in constructing and critiquing mathematical arguments.

• Find the Value of an Angle
Students will use what they know about angles in diagrams to find the value of a missing angle.
Resource:
Find the Value of an Angle

Students will use what they know about angles in diagrams to find the value of a missing angle.

All Resources From:
• Unit 2