# Math sec. 8.1-8.2

## 17 terms

### Lines

made up of a series of points that extend in two opposite directions

### point

exact location in space

### segment

the part of a line consisting of two endpoints and all points between them

### ray

A part of a line, with one endpoint, that continues without end in one direction

### collinear

points that lie on the same line

### plane

A flat surface that goes on forever in all directions

### intersecting lines

lines that have exactly one point in common

### Parallel lines

Lines that have no points in common

### skew lines

lines that are not parallel and do not intersect

### angle

two rays with a common endpoint, called the vertex

### vertex

The common endpoint of an angle

### acute angle

less than 90 degrees

### right angle

an angle that measures 90 degrees

### obtuse angle

measures between 90 and 180 degrees

### straight angle

an angle whose measure is 180 degrees

### perpendicular lines

Two lines that intersect to form right angles

### degrees

a unit for measuring angles