find the surface area and volume of a sphere of radius 3 feet?

Answer 1

I see that you posted similar questions. Rather than give you the answer, I'll try to explain it to you.

First go to this site to get all the key formulas:
http://math.about.com/library/blmeasurement.htm

We see that the key formulas for spheres are:
Volume = 4/3 pr^3
Surface = 4pr^2
Where p represents pi and r represents the radius.

Part 1: find the surface area
We see that the formula for Surface = 4pr^2
We know that r = 3 ft
By plugging in 3 into r and p ~ 3.14
Surface = 4*3.14*3^2

Part 2: volume of a sphere
We see that the formula for Volume = (4/3)pr^3
By plugging in r and pi we can derive the volume.

Hope this helps you in understanding what's going on. If you have any questions, feel free to leave an additional comment and I'll try to answer it.

Answer 2

SA of sphere is 4 pi r^2
vol of sphere is 4/3 pi r^3

just substitute radius and solve.

Answer 3

V = (4/3)π r³
V = (4/3)π (27) ft³
V = 36 π ft³
V = 113 ft ³ ( to nearest ft³)

S.A. = 4 π r ²
S.A. = 4π (9) ft ²
S.A. = 113 ft ²

Now that is interesting that they have same numerical value.