Question

Help please

Answer 1

sure

Answer 2

ill try

Answer 3

do you think you can write it down

Answer 4

@agent0smith

Answer 5

@SQL_Server

Answer 6

\[\large SA = 4\pi r^2\]There is 2 ways to do this:

Method 1) use the SA formula to find the r of the small sphere. Then find the SA of the big one.

Method 2) use the fact that since SA depends on r^2, when you *double* the radius from r to 2r, you *quadruple* the SA.

Answer 7

The small one is \[8100\]

Answer 8

The small what? The r for the small cannot be that large.

Method 2 is easier btw.

Answer 9

i got 8100pi

Answer 10

Notice you were given the SA for the small, NOT the radius.

Answer 11

i did \[SA=(4)( \pi )(45)^{2}\]

Answer 12

See last post

Answer 13

well would it be 45*2 then

Answer 14

\[45=(4)( \pi )r^{2}\]solve for r

Answer 15

1.89

Answer 16

Looks right

Now find the SA for the big one. You know the radius is 2 times the small one.

Answer 17

the SA formula right

Answer 18

Yes

Answer 19

179.55

Answer 20

you could keep it exact using

Method 2) use the fact that since SA depends on r^2, when you *double* the radius from r to 2r, you *quadruple* the SA.

Old SA was 45, new SA will be 4*45

Answer 21

So A

Answer 22

because it would be squared right

Answer 23

Correct