Which measurements is closest to the circumference of the base of the observatory in feet?

anyone? find the second, fifth, and ninth terms of a sequence where the first term is 65 and the common difference is -7. 72, 93, 121 72, 79, 86 58, 37, 9 58, 51, 44

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

The amount of data left on the cell phone six gb for 81.5 gb of data is used how much data is available at the beginning of the cycle