As you learn about major and minor key signatures, it is important to understand what a RELATIVE KEY is. Major keys and minor keys are related in that some of them share their key signature. In fact, each major key has a relative minor key. They share a key signature, but each of them has a different tonic.
It is relatively straight forward to find the relative minor key of a major scale. To find a relative minor key, you must find the 6th note (or the submediant) of the major scale. For example, we know that the key of C has no sharps or flats. The notes of the C major scale are C-D-E-F-G-A-B-C. So what is the relative minor of C major? If you guessed A minor, you would be correct.
Now what if you wanted to go the other way? To find the relative major key of a minor scale? Well, that is simple as well – except for instead of taking the 6th note of the scale, you would take the MEDIANT (3rd note) of the minor scale. I haven’t told you how to construct a minor scale yet, but the third note of the A minor scale is C. Take my word for it.
So now you have the complete picture: C major and A minor are related in the sense that they share the same key signature (no flats and no sharps). The table below shows the other relative major and minor keys.
While improvising or composing music, it is important to understand relative major and minor keys. They are often used in the same piece of music as a way to add musical interest and variety.