Question

Kirsten used a log to make an umbrella stand. The log was 28 in. tall and had a radius of 7.5 in. Kirsten cut a cylindrical shape, with a radius of 5.5 in., out of the center of the log.

After Kirsten cuts out the cylinder, what is the volume of the remaining portion of the log? Use 3.14 to approximate pi, and express your answer to two decimal places.

_______in^3

http://static.k12.com/calms_media/media/1565500_1566000/1565640/1/5bc2b238e1b24ddfb4dfcab604d3ad0d5ec92a3b/MS_IMC-1401119-110021.jpg

Answer 1

I did 7.5 times 7.5

Answer 2

can you find the volume of the initial log?

Answer 3

and 5.5 times 5.5 :/ they gave me 2 radius :/

Answer 4

volume of a cylinder is the area of the circle * length

Answer 5

so use 7.5?

Answer 6

find the volumes of the two cylinders first

Answer 7

kk the volume of 7.5 times 7.5 is 56.5

Answer 8

and

Answer 9

the volume of 5.5 times 5.5 is 30.25

Answer 10

correct?

Answer 11

no, what is the area of a circle?

Answer 12

?

Answer 13

i don't get it

Answer 14

You ditched me o.o

Answer 15

@mick14731

Answer 16

so the area of a circle is \[A = \pi r ^{2} \]
have you seen that before?

Answer 17

No i've seen V = and the rest

Answer 18

V = πr2h.

Answer 19

you can't get the volume without the are of the end.

Answer 20

its not pi*r*2*h its \[\pi * r ^{2}*h =V\]

Answer 21

\[r^{2}= r*r\]
so for the big log r= 7.5in, and h = 28 in so what is the volume?

Answer 22

so 7.5 times 7.5 = 56.25 times 28?

Answer 23

@mick14731

Answer 24

what about pi?

Answer 25

i'm gonna do the pi wants i do 56.25 times 28

Answer 26

and 56.25 times 28 is 1575

Answer 27

and 1575 times 3.14 is 4945.5

Answer 28

just write out the volume equation without multiplying any of the numbers yet.

Answer 29

i'm confused -.-

Answer 30

Can you just show me in number what to do and i'll understand

Answer 31

V= pi * r * r * h
V= 3.14 * 7.5 * 7.5 * 28 that is the log at first

Answer 32

Thas what i did!!!

Answer 33

I DID THA! you didn't look at what i said!

Answer 34

UGH

Answer 35

@mick14731 !!!!!!!!

Answer 36

If you look at the top -.-

Answer 37

so how does that number help you?

Answer 38

-.-

Answer 39

is the answer 4945.5!?

Answer 40

no, if i had a cube with side = 3 and i cut a square hole down the middle with sides 1, what is the remaining volume?