# Exploring Angle Relationships with Triangles

- Author:
- Jenny Novak

- Topic:
- Triangles

## Directions

For each of the following applets, explore the given angle relationships in order to make generalizations about the relationships between the angles.

## Part I: Angle Sum in a Triangle

What do you notice about the measures of the angles in triangle ABC?
Move points A, B, and C to create different triangles. What do you notice about the angles in the new triangle? Will this always be true?

## 8.G.A.5 Angle Sum

## Part II: Exterior Angles 1

Angles BAD, CBE, and ACF are exterior angles of triangle ABC. What do you notice about the exterior angles of this triangle?
Move points A, B, and C to create different triangles. What do you notice about the exterior angles in the new triangles? Will this always be true?

## 8.G.A.5 Exterior Angles 1

## Part III: Exterior Angles 2

Angles CAH, ABI, and BCJ are also exterior angles of triangle ABC. What do you notice about the angles of this triangle?
Move points A, B, and C to create different triangles. What do you notice about the exterior angles in the new triangles? Will this always be true?