Question

Find the surface area of the sphere with the given dimension. Leave your answer in terms of pi.
1.) Radius of 60m.
2.) Diameter of 14 cm.

Answer 1

@jim_thompson5910

Answer 2

http://0.tqn.com/d/math/1/0/I/F/spherer.gif

Answer 3

still need help?

Answer 4

If the formula for the surface area of a sphere is S.A. = 4*pi*r^2 what would the surface area be?

Answer 5

hold on. doing other work. brb

Answer 6

what is r?

Answer 7

r is the radius of the sphere

Answer 8

I got 48,960...:/

Answer 9

oh wait. 45,216.

Answer 10

That's correct, don't forget to include your units

Answer 11

the answers are in pi

Answer 12

and none are 45,000

Answer 13

Well then it will be (4*r^2)*pi

Answer 14

What's 4*60^2 ?

Answer 15

14,400. :) Thanks.

Answer 16

Yup :)

Answer 17

is it the same equation for the second one?

Answer 18

In the second one you're given the diameter of the sphere which is double the radius

Answer 19

so, what would the equation be?

Answer 20

It would be the same equation just divide the diameter by two to get your radius

Answer 21

so, instead of putting in 14, it would be 7?

Answer 22

Can you help with 3 more please? :)

Answer 23

Find the volume of the sphere shown. Give each answer rounded to the nearest cubic unit.

Answer 24

The equation for the volume of a sphere is
\[\Large V = \frac{4\pi r^3}{3}\]

Answer 25

Would the equation be the same for this one?

Answer 26

Yes, but you need to half the diameter again to get the radius

Answer 27

okay, what about this one:
"The volume of a sphere is 5,000pi m^3. What is the surface area of the sphere to the nearest square meter?"

Answer 28

Well if the surface area is 5000pi and we know that the equation for the volume of a sphere is 4/3 * pi * r^3 we need to set them equal to each other and solve for the radius (so we can use it to find the volume)

Answer 29

how?

Answer 30

\[\Large 5000 \pi = 4\pi r^2\]

Answer 31

314,000,000? :/

Answer 32

First you should cancel pi from both sides

Answer 33

k

Answer 34

then what?

Answer 35

Then we will have 4r^2 = 5000
What should you do next to have only r on one side

Answer 36

get rid of the r by the 4?

Answer 37

@Hunus

Answer 38

We need to divide the 4 to get rid of it

Answer 39

so, it would be "2^2*5000"?

Answer 40

\[\frac{4r^2}{4}=\frac{5000}{4}\]

Answer 41

what next?

Answer 42

If we have what r^2 equals what should we do to both sides to get r

Answer 43

cross multiply?

Answer 44

What about the square root of r and the square root of 5000?

Answer 45

ugh. I'm stuck.

Answer 46

If r^2 = 5000
then \[\sqrt{r^2} = r = \sqrt{5000}\]

Answer 47

then what??

Answer 48

@Hunus

Answer 49

@Nurali please help

Answer 50

never mind. I got it

Answer 51

ok