What is the key signature for the scale of A major?

The key signature for the scale of A major contains three sharps. This can be understood by recalling the order of sharps in key signatures, which follows a specific pattern: F#, C#, G#, D#, A#, E#, and B#.

A major is the key that starts on the note A and includes the notes A, B, C#, D, E, F#, and G#. To derive the key signature, one can also use the circle of fifths, where moving clockwise from C major (which has no sharps) adds one sharp for each step. Following this sequence, we find that A major, being the third step clockwise, has three sharps: F#, C#, and G#. This solidifies the understanding that when identifying key signatures, it’s essential to either memorize the order of sharps or refer to the circle of fifths for accurate results.