Identify the different parts of an angle.


    Present how to name an angle (), and how to identify the three parts of an angle (,,).


    Demonstrate how to construct an angle.


This packet should help a learner seeking to understand the different parts of angles and how to construct an angle.

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Introduction to Angles

This video provides an introduction to angles and their parts.

Source: JasmineWanek on Guaranteach

Parts of Angles

As the previous video explained, angles are made up of three parts: the vertex, and two rays or line segments. Here are some more in-depth descriptions of these parts:


A vertex is a point - specifically, the point where the two rays or line segments that make up an angle meet. A point is a one-dimensional object, meaning it has no length, width, or height. All a point does is define a single location in space: it doesn't take up any area itself.


A ray is a straight line that extends infinitely in one direction. Unlike a line, which extends infinitely in both directions, and a line segment, which is finite in both directions, a ray only extends infinitely in one direction, and has a particular starting point. When two different rays start from the same point (the vertex), they form an angle.

Line Segment

A line segment is a straight line with two endpoints, meaning it is finite. When two line segments share an endpoint (the vertex), they form an angle.


Here is a graphic that compares rays and line segments with lines.


As you can see, the arrows show that lines extend infinitely in both directions, rays extend infinitely in one direction, and line segments are finite.


For more information on points, rays, and line segments, visit the Points, Lines, and Planes learning packet: http://www.sophia.org/packets/points-lines-and-planes--3.


Identifying Angles

This video explains how to name angles and further explores the parts of an angle.

Source: JasmineWanek on Guaranteach

Constructing an Angle

This video demonstrates how to copy an angle using a straightedge and a compass.

Source: markkings314 on Youtube