Question

V = πr2h
h = 3xr = 9
V = π(3)2(9) = 81π ≈ 254.34 inches3

Answer 1

where did the x come from it went from pi2h and then 3xr where did the x come from?!

Answer 2

@563blackghost

Answer 3

I'm guessing your solving for the volume of a cylinder cause of the formula, but where exactly did you get this solution? And is there a diagram for this problem?

Answer 4

http://prntscr.com/inp4vj

Answer 5

Okay I see.

Answer 6

If you look in the beginning the question states `"a height that is triple the radius"`.

This would indicate that we do not know what the radius is so we have it as a variable `r`.

Though the `x` is unusual. It might be indicating 3x `x` being the variable for the radius.

@dude what do you think?

Answer 7

ok lol

Answer 8

I agree with ya ghost :3

Answer 9

I mean if the `x` means multiply then it would be represented as a dot.

Answer 10

how did he get 3?

Answer 11

`triple` = `3`.

So we are multiplying the radius by `3`.

Answer 12

Okay I understand

Answer 13

awesome >.<

is there anything else that you don't understand?

Answer 14

it says Use 3.14 for pi. Does that mean for every question that I do that says that whatever answer i get i have to divide it by pi?

Answer 15

grammar lol

Answer 16

When you are told to `use 3.14 for pi` it simply means to substitute it in there for whatever formula you are using being it an area for a circle, circumference etc.

Answer 17

They state this because sometimes they will make you keep it in terms of `pi`.

Answer 18

Does that mean whatever answer I get I have to divide it by pi?

Answer 19

No.

When you plug in pi as `3.14` you have already completed the stated use.

The final answer is your final answer.

Answer 20

then why does it go 81pi to 254.34 inches3

Answer 21

That's simply becuase they kept the terms of `pi` then plugged in `pi` as `3.14`. This resorts to them having to multiply it.

If you plugged `pi` in the beginning and solved all the way through you would come to the same answer.

Answer 22

so that means when it says use pi all I do is plug in pi

Answer 23

yup

Answer 24

how did they get 4/3 pi27= 36?

Answer 25

Well the formula for volume of a sphere is \(\large\bf{\frac{4}{3} \pi r^{3}}\).

They are told the diameter of the sphere is `6`, but to find the radius you divide it by `2` and get `3`. So the `radius = 3`.

So they plug that in.

\(\large\bf{\frac{4}{3} \pi (3)^{3}}\)

So we simplify \(\bf{3^{3}} = 3 \times 3 \times 3 = 9 \times 3 = {\large\bf{\color{red}{27}}}\)

So we get \(\large\bf{\frac{4}{3} \pi (27)}\) in which we `multiply 4 by 27` then `divide by 3` to get 36 `we keep pi in terms of pi`.

\(\Large\bf{\frac{4 \times 27}{3} \pi (27) \rightarrow \frac{108}{3}\pi \rightarrow \color{red}{36 \pi}}\)

Answer 26

whoops that `pi (27)` is a mis type it is suppose to be just `pi`.

Answer 27

why do we do 9 times 3?

Answer 28

i thought we used up all the threes

Answer 29

lol

Answer 30

It's because of the powers.

`REMEMBER THAT HOLDING TO A POWER IS MULTIPLYING ITSELF`.

\(\large\bf{3^{3} = 3 \times 3 \times 3}\)

We simply start pairing to solve. So we do `3x3` first.

\(\large\bf{3 \times 3 = 9}\)

\(\large\bf{3 \times 3 \times 3 \rightarrow 9 \times 3}\)

We are left with one 3 so we multiply that by 9.

\(\large\bf{3 \times 9 \rightarrow \color{red}{27}}\)

Answer 31

yea lol i just got confused cause you did 3x3x3=9

Answer 32

Thank you

Answer 33

No problem!

If you have any other questions and I'm free just tag meh ;)

Answer 34

lol ok