How do you find the square footage of a room next to a curved wall? I have a room next to 2 long walls - both 13'...

I have a room next to 2 long walls - both 13' and 2 short walls -both 7'5" in the corner is a curved wall - in the region of a 1/4 circle. the length of the curved wall is almost 9'3" (hard to measure by myself). Can anyone support?
Answers:    you can always standard is simpliest by rounding off the room to a square and consequently just tag on 5-10% more for the "missing" footage. To guess to the proximity is not a terrable thing.
Approximate is fine for most projects. Just means from the furthest points on opposite walls.