## 1. Inscribed Triangles

## 2. Circumscribed Triangles

## 3. Definition

### 3.1. Task

### 3.2. Prerequisites

## 4. Properties of Triangles

### 4.1. Having 3 sides & 3 angles

### 4.2. All triangles are convex

### 4.3. 3 interior angles add to 180°

### 4.4. Measure of an exterior angle equals the sum of the measures of the two non-adjacent interior angles

### 4.5. The acute angles of a right triangle are complementary

## 5. How to Identify A Triangle

### 5.1. Types of Triangles

5.1.1. Classify by Sides

5.1.2. Classify by Angles

### 5.2. Measure a Triangle

5.2.1. Perimeter

5.2.2. Area