## 1. Congruence & Transformations

### 1.1. Dilation

1.1.1. A transformation in which the lines connecting every point P with its preimage 'P all intersect at a point c known as the center of the dilation

### 1.2. Isometry

1.2.1. A transformation that dies nit change the size or shape of a figure

### 1.3. rigid transformation

1.3.1. Another name for isometry

## 2. Classifying Triangles

### 2.1. acute triangle

2.1.1. A triangle that has 3 acute angles

### 2.2. equiangular triangle

2.2.1. A triangle with three congruent angles

### 2.3. right triangle

2.3.1. A triangle with one right angke

### 2.4. obtuse triangle

2.4.1. A triangle with one obtuse angle

### 2.5. equilateral triangle

2.5.1. A triangle with three congruent sides

### 2.6. isosceles triangle

2.6.1. A triangle with at least two congruent sides

### 2.7. Scalene Triangle

2.7.1. A triangle with no congruent sides

## 3. Angle Relationships in Triangles

### 3.1. auxiliary

3.1.1. A line drawn in a figure to aid in a proof

### 3.2. corollary

3.2.1. A theorem whose proof follows directly from another theorem

### 3.3. interior

### 3.4. exterior

### 3.5. interior angle

3.5.1. An angle formed by two sides of a polygon with a common vertex

### 3.6. exterior angle

3.6.1. An angle formed by one side of a polygon and the extension of an adjacent side

### 3.7. remote interior angle

3.7.1. An interior angle of a polygon that is not adjacent to the exterior angle

## 4. Congruent Triangles

### 4.1. corresponding angle

4.1.1. Angles in the same relative position in two different polygons that have the same number of angles

### 4.2. corresponding sides

4.2.1. Sides in the same relative position in two different polygons that have the same number of sides

### 4.3. congruent polygons

4.3.1. Two polygons whose corresponding sides and angles are congruent

## 5. Triangle Congruence:SSS and SAS

### 5.1. triangle rigidity

5.1.1. A property of triangles that states that if the side lengths of a triangle are fixed, the triangle can have only one shape

### 5.2. included angle

5.2.1. The angle formed by two adjacent sides of a polygon

## 6. Triangle Congruence: ASA, AAS, and HL

### 6.1. Included side

6.1.1. The common side of two consecutive angles of a polygon.