Piano--playing in what key?
(Girardville, PA 17935)
How do I know what key in piano I am playing in?
I depends on whether you are reading music or you are playing chords without printed music.
If you are reading music, the "Key Signature" will tell you what key you are playing in. All you have to do is match up the number of sharps or flats with your knowledge of key signatures.
If you need to learn about key signatures, please visit Understanding Music Key Signatures
On the other hand, you might be playing chords and want to know what key you are playing in so that you can do a solo (for example).
That requires a slightly different perspective.
You need to have a knowledge of chord progressions so that you will know which chords go together and will therefore be able to identify the key of various combinations of chords.
For some in depth lessons about Chord Progressions, please visit:Music Chord Progressions
Hope this helps--let me know.