17. the colosseum in rome was the largest amphitheater built in the roman empire. the interior of the colosseum is a perfect circle. the roof of this enormous amphitheater was about 600 feet in diameter. if the center of the colosseum is assumed to be at origin, then write an equation for the circle that represents the roof of the colosseum.

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?