The key of E major
E F♯ G♯ A B C♯ D♯
4 sharps: F♯ C♯ G♯ D♯. Relative minor: The key of C♯ minor.
The triads of the key
I
E | ii
F♯m | iii
G♯m | IV
A | V
B | vi
C♯m | vii°
D♯° |
The seventh chords
Imaj7
Emaj7 | ii7
F♯m7 | iii7
G♯m7 | IVmaj7
Amaj7 | V7
B7 | vi7
C♯m7 | viiø7
D♯m7♭5 |
E major scale
Open it in the app: 6. Harmony, in E