# Geom Chap 8 Sec 1-2-3

## 17 terms

### Polygon

A figure formed by 3 or more coplanar segments with 2 segments at each vertex

### Sides of a Polygon

The segments that form the polygon

### Diagonal

The segment joining 2 vertices not on the same side

### Interior Angle Sum Theorem

The sum of the interior angles of a convex polygon is equal to the number of sides minus 2 times 180 (S=(N-2)180)

### Exterior Angle Sum Theorem

The sum of the exterior angles (1 angle at each vertex) of a polygon is 360

### Parallelogram

A quadrilateral with two sets of opposite sides that are parallel

are congruent

are congruent

### The consecutive angles of a parallelogram

are supplementary

### Each diagonal of a parallelogram

separates the parallelogram into 2 congruent triangles

### If the parallelogram has one right angle,

then it has four right angles

### The diagonals of a parallelogram

bisect each other

### If 2 sets of opposite sides of a quadrilateral are congruent,

then it is a parallelogram

### If both sets of of opposite angles are congruent,

then the quadrilateral is a parallelogram

### If the diagonal of a quadrilateral bisect each other,

then it is a parallelogram

### If the same pair of opposite sides of a quadrilateral are congruent and parallel,

then it is a parallelogram

### If its a parallelogram

Opposite sides parallel, opposite sides congruent, opposite angles congruent, consecutive angles supplementary, diagonals bisect each other, if 1 right angle then 4 right angles, and each diagonal forms 2 congruent triangles