Which piecewise relation defines a function?

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

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?

3.4a=57.8 what is the the value of a