Exterior Angle Theorem
Grade 7 students in Big Ideas Math Advanced 2 (Chapter 3: Angles and Triangles) learn the Exterior Angle Theorem: an exterior angle of a triangle equals the sum of the two non-adjacent remote interior angles.
Key Concepts
Property An exterior angle is formed when one side of a triangle is extended outward. It forms a linear pair (summing to 180°) with its adjacent interior angle.
The Exterior Angle Theorem states that the measure of an exterior angle equals the sum of the two non adjacent (remote) interior angles:.
$$m\angle\text{ext} = m\angle A + m\angle B$$.
Common Questions
What is the Exterior Angle Theorem in 7th grade?
An exterior angle of a triangle equals the sum of the two remote interior angles. If remote angles are 40 and 60, the exterior angle is 100.
How do you use the Exterior Angle Theorem to find a missing angle?
Add the two remote interior angles to get the exterior angle, or subtract one remote angle from the exterior angle to find the other.
What chapter in Big Ideas Math Advanced 2 covers exterior angles?
Chapter 3: Angles and Triangles in Big Ideas Math Advanced 2 (Grade 7).
Why does the exterior angle equal the sum of remote interior angles?
Both the exterior angle and the two remote interior angles relate to the same 180-degree angle sum, making them equal.