I'm guessing you mean in Photoshop so you would
1. click the ruler tool
2. drag it along the line you know is straight
3. on the options bar, click straighten
hope this helps :)
Answer:
Photograph of painting by Pablo Picasso titled Violin
1. staff
2. a white key
3. tell musicians how to figure the names
4. treble and bass
5. it tells you where g is
6. a b c d e f g
7. leger lines
8. bass
9.5
not sure of 10
You can have some of mine if they even exist
