A **point** is a precise location with no dimensions.

A **line segment** is a straight path with endpoints.

A **ray** is a straight path extending infinitely in one direction from an endpoint.

A **line** is a straight path extending infinitely in both directions.

An **angle** is formed by the intersection of two line segments, rays, and/or lines.

In diagrams, points are typically represented by a dot.
A letter is typically used to label the dot.
In the diagram [*right*], there are 4 labeled points.
The points are identified as point *A*, point *B*, point *C*, and point *D*. | |

In diagrams, line segments are typically represented by a line with endpoints.

A letter is typically used to label an endpoint.

The endpoints are used for identification.

In the diagram, there are 3 identifiable line segments.

The line segments are: line segment *AB*, line segment *AC*, and line segment *AD*.

The line segments can also be referenced as: AB, AC, and AD.

In diagrams, rays are typically represented by a line with an arrow

extending from an endpoint. A letter is typically used to label the endpoint.

The endpoint and a second labeled point on the ray are used for identification.

The endpoint is listed first.

In the diagram, there are 3 identifiable rays.
The rays are: ray *AB*, ray *AC*, and ray *CA*.

The rays can also be referenced as: $\overrightarrow{\text{AB}}$, $\overrightarrow{\text{AC}}$, and $\overrightarrow{\text{CA}}$.

In diagrams, lines are typically represented by a line with arrows pointing in opposite directions.
Two labeled points on the line are often used for identification.

Sometimes a diagram uses a number or a single lowercase letter, near one of the arrows, to label a line.

In the diagram, there is 1 identifiable line.

The line is line *AC*, and can also be referenced as $\overleftrightarrow{\text{AC}}$.

Angles are often identified by 3 letter-labeled points (1 on each

leg and the vertex).

The vertex point is listed in the middle.

Sometimes a diagram uses a number or a single letter, at the vertex, to label an angle.

However, a single letter label is usually not appropriate if there is more than 1 angle associated with that letter.

In the diagram, the identifiable angles are: angle

*BAC*, angle

*BAD*, and angle

*CAD*.

The angles can also be referenced as: ∠

*BAC*, ∠

*BAD*, and ∠

*CAD*.