Hi there!

Use the kinematic equation to solve for acceleration:

Where:
vf = final velocity
vi = initial velocity
t = time
Plug in the given values:

The y has to be negative but the x positive. So that leaves only (3,-4)
The formula for surface area of a sphere: A = 4 pi r^2.
Since the radius is 30 m then A = 4pi30^2.
30^2 x 4 =3600
A=3600pi m
When you find the mean you add all of them together. Then you divide your answer by how many numbers there are that you added.
So what I did was add 29+30+28+32+29+31+27= 205
then divide 205 by 7 and you get 29.285