How do you transpose A major to C major?

To transpose from A major to C major, you need to shift each note up by a minor third interval, as C major is three half steps higher than A major. In A major, the notes are A, B, C#, D, E, F#, G#, and they become C, D, E, F, G, A, B in C major. Essentially, you can take each chord or melody in A major and move it up to the corresponding notes in C major to achieve the transposition.