# Geometry

## 38 terms · Chapter one

### line

A endpoint that never ends or begins, 2 arrowheads

### line segment

a set of points with an end and a beggining

### ray

conists of points with a beggining and no ending

### intersection

the set of points that figures have in common

### coordinate

the real number that corresponds to a point

### distance

the space between two points

### congruent segments

line segments that have the same length

### midpoint

the point that splits it in half

### segment bisector

a line segement that splits a segment equally in half

### midpoint formula

(X1+X2/ 2, Y1+Y2/2)

### distance formula

(square root) (X2-X1)2 +(Y1-Y2)2

### angle

two different rays with the same endpoint

### sides

the rays of the angle

### vertex

the endpoints of an angle

180` angle

### acute

smaller then 90 degrees

### right

an angle equal to 90 degrees

### obtuse

an angle greater than 90 degrees

### congruent angles

two angles with the same measure

### angle bisector

a ray that splits an angle equally in half

### complementary angles

two angles that equal to 90 degrees

### supplementary angles

two angles that equal 180 degrees

two angles that share a common vertex and side, but have no common interior points

### linear pair

two adjacent angles with common sides that are opposite rays

### vertical angles

two angles with sides that form two pairs of opposite rays

### polygon

a closed plane figure with the following properties

### sides

a shape formed by three or more line segments

### vertex

the endpoint of a side

### convex

if no line that contains a side of the polygon contains a point in the interior of the polygon.

not convex

### equilateral

all sides are congruent

### equilangular

all angles in the interior of the polygon are congruent

### regular

is a convex polygon that is both equilateral and equalangular

2l+2w= P

P=a+b+b

A=1/2bh

3.14d=C

A=3.14r2