1. After this slide show you should know:
Put the slide show on full screen.
Then click to move through the slides
After this slide show you should know:
What the terms point, line, interval, vertex and arms of an angle mean
How to label an angle
How to identify named angles in diagrams
Read through these slides and complete the missing blanks on the rest of your worksheet

2. Points, Lines and Intervals
Points are always labelled with capital letters.
Below are the points A and B
A line continues to infinity, which is why it has arrows on both ends. This is the line AB B
An interval is similar to a line, but is only the part of the line between 2 points. This is the interval AB. A A B

3. What are an angle, a vertex and the
arms of an angle?
The red shaded part is the angle. An angle is a measure of rotation
The arms of the angle are the 2 lines or intervals that meet to form the angle. The intervals AB and AC are the arms of this angle
In everyday language, a vertex is a corner of a shape. It is the point where 2 arms of an angle meet. The marked angle is at vertex A.

4. How to name angles P Q R S
How would we name the red shaded angle?
The red angle can be written as or
It is named according to points on the arms of the angle, and the vertex.
The letter at the centre of the 3 letters naming the angle is always the vertex. Here that is Q
Two angles with a common arm are called adjacent angles. Here is adjacent to

5. Practice naming angles
Think what the names of the shaded angles are and then click to check if you are right: A B C D E or or or or

6. Practice finding angles
Look at diagram and find each angle listed. Think about its value and fill it in on your worksheet. Click to check and mark your answers on your worksheet.
=34°
=32°
=68°+62°
=130°
=39°+32°
=71°
=70°
=40°+68°
=108°