During a certain 25-year period, the consumer price index (CPI) increased by 99%, but during the next 25-year period, it increased by only 1%. Which of these conditions must have existed during the second 25-year period?

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)

if you are looking for the unit rate then the answer would be 9 because unit rate is distance divided by time.

step-by-step explanation: