4th Grade Math - Geometry Terms Lesson
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, 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: , , and .
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 .
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.