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 :)
It was shut down 40 years ago! if you're referring to the book, "fahrenheit 451"
Answer:
Im not fully sure, but I think that it is a drawing by leonardo da vinci, and it was one of his ideas for a thing kind of like a helicopter.
