How many significant figures are in the measurement 0.020 km?
a. 1
b. 2
c. 3
d. 4

i think it is 2

Step-by-step explanation:

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)

throw the computer

step-by-step explanation: