1. Objective: Learn to name and measure angles.

2. Lines and Rays: A line extends without end in both directions.
Example: Line AB
The symbol for line is AB
Rays, like the sun’s rays, start at one point and continues indefinitely (without end) in one direction.

3. Angles: When 2 rays have the same endpoint they form an angle.
The 2 rays are the sides of the angle and the common endpoint is the vertex.
You can use the angle symbol ( < ), the vertex, and a point on each side to name the angle. You can use the vertex alone, or a number to name the angle.
For example: <B , <ABC , < CBA

4. Angles can be measured in degrees:
An Acute Angle: has a measure of less than 90 degrees.
Example:
A Right Angle: has a measure of exactly 90 degrees.

5. A Straight Angle: has a measure of exactly 180 degrees.
An obtuse Angle: has a measure greater than 90 degrees and less than 180 degrees.
Example:
A Straight Angle: has a measure of exactly 180 degrees.