Question

The volume of a sphere is 4,000 m3. What is the surface area of the sphere to the nearest square meter @Directrix

Answer 1

We have both volume and surface area this time.

Answer 2

The only thing to know about a sphere is its radius.
So, we will have to get that first.

Answer 3

V = 4/3 * π * r³
4,000 = 4/3 * 3.14 * r³
3000/3.14 = r³

Solve for r

Answer 4

kinda confused by all the numbers

Answer 5

Yes, I used the online calculator You can see the result at this link:

http://www.wolframalpha.com/input/?i=4%2C000+%3D+4%2F3+*+pi+*+r%C2%B3

Answer 6

r = 9.84

Answer 7

Now, to get surface area.

A = 4 * π * r²

A = 4 * π * (9,84)²

Answer 8

approximate the pi

Answer 9

Yes. Approximate the pi unless the instructions tell you to leave the answer in terms of pi.

Answer 10

1216.75 which to the nearest square meter is 1217 square meters.

Looks a bit odd.

Answer 11

no it doesn't say that so i guess i do

Answer 12

the closest to it is 1219

Answer 13

We should not be that far off. Let me see.

Answer 14

I allowed for more digits in the approximation of r.

A= 4 * π * (9.8475)²

A = 1218.6 so that goes to 1219

Answer 15

i got it ?

Answer 16

1219m^2

Answer 17

When you are taking the timed test, if you get close to the correct answer, don't go back to add extra digits of a number. Because on multiple choice, go with anything close.

Answer 18

good advice ,ill keep that in mind

Answer 19

ready for the last one?

Answer 20

Yes.