
- Angles, Lines, and Polygons
- Home
- Measuring an angle with the protractor
- Acute, obtuse, and right angles
- Naming segments, rays, and lines
- Identifying parallel and perpendicular lines
- Acute, obtuse, and right triangles
- Classifying scalene, isosceles, and equilateral triangles by side lengths or angles
- Finding an angle measure of a triangle given two angles
- Naming polygons
- Drawing and identifying a polygon in the coordinate plane
Naming segments, rays, and lines
Point − A basic geometric entity. It that has no length, width or height. It is described only by its position.

This is a point Q
Straight line − A set of points that extend indefinitely in both directions.

This is an example of line UT.
A line is a continuous set of points that continues on indefinitely. The arrow indicates infinite length.
Line segment − A part of a line with two end points say X and Y.

This is an example of line segment XY.
Ray − A part of a line with one endpoint. A ray extends indefinitely in one direction.

This is an example of ray DT.
Identify given figure as a line segment, a ray or a line. Then name the figure using the given points.

Solution
Step 1:
The given figure has one end point and continues indefinitely in one direction. Therefore, it is a ray.
Step 2:
The ray is named as FG.
Identify given figure as a line segment, a ray or a line. Then name the figure using the given points.

Solution
Step 1:
The given figure continues indefinitely in both directions. So it is a line.
Step 2:
The line is named as CD.