could it be? OMG math

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

So today we had the state test that we have to take thanks to NCLB, for my sophomore class. It was Math. I practically finished all 62 questions in about an hour and a half. Except one question:

If I replicated it correctly from memory. Anyways, I spent like the whole day trying to figure out the answer and I just couldn't. I know I will feel like a douche when you guys tell me right answer. But I just kept on trying and trying with everything I could think of and nothing. So now my perfect score streak since 1st grade is broken. :cry:

After some cursing out loud and getting escorted to the gym to finish there, I gave up and randomly selected B.

boast · **Joined:** Jan 2007 **Posts:** 477 **Location:**

was there an E. None of the above

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

you sure the correct answer is within those options? lol
idk if im right cuz this is old stuff but the volume of a cilinder is the area of the circunference times the height. area of circunference = pi*radius^2, and height = h.
so:
r = x/2, h = 6x
V = pi*(radius)^2*height
V = pi*(x/2)^2*6x
V = pi*(x^2/4)*6x
V = (3/2)*pi*x^3

so the answer is E) none of the above. or F) this test sucks balls.

Reise · **Joined:** May 2006 **Posts:** 6650 **Location:**

I suck at this stuff but I know the answer isn't A or B.

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

Yeah my algebrator says that the answer is 3PIx^3 which is what I got when I first worked out the problem.

damn TAKS creators.... no there was no E.

_Angels · **Joined:** Nov 2007 **Posts:** 707 **Location:**

evilpeta wrote:

you sure the correct answer is within those options? lol
idk if im right cuz this is old stuff but the volume of a cilinder is the area of the circunference times the height. area of circunference = pi*radius^2, and height = h.
so:
r = x/2, h = 6x
V = pi*(radius)^2*height
V = pi*(x/2)^2*6x
V = pi*(x^2/4)*6x
V = (3/2)*pi*x^3

so the answer is E) none of the above. or F) this test sucks balls.

You are my new hero...

Locketart · **Joined:** Mar 2007 **Posts:** 2119 **Location:**

I thought it was 6/4x^3 also.

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

_Angels wrote:

evilpeta wrote:

you sure the correct answer is within those options? lol
idk if im right cuz this is old stuff but the volume of a cilinder is the area of the circunference times the height. area of circunference = pi*radius^2, and height = h.
so:
r = x/2, h = 6x
V = pi*(radius)^2*height
V = pi*(x/2)^2*6x
V = pi*(x^2/4)*6x
V = (3/2)*pi*x^3

so the answer is E) none of the above. or F) this test sucks balls.

You are my new hero...

but isn't 6*1/2=3? or i'm i a math noob?

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

you don't get to multiply 6 times 1/2 since the 1/2 turns into 1/4 due to radius squared.
lets take X out of the equation so it's easier to see.
radius = 1/2, height = 6
Volume = pi * (radius)^2 * height
V = pi * (1/2)^2 * 6
V = pi * 1/4 * 6
V = pi * 3/2

now you can just assume it's x^3 since its a volume, volume is measured in units ^3
meters^3, etc etc.

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

Like evilpeta said, answer is: (3/2)pi(x^3).

pi*r^2*h
Pi*((1/2)x)^2)*(6x)
=Pi*(1/4)*(x^2)*(6x)
=Pi*(3/2)*(x^3)
=(3/2)*pi*(x^3)

Answer isn't there.

EDIT: Doh evil replied again.. easier to understand the way he put it.

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

still.. now that im thinking that 2/3 could of been a 3/2

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

You're messing up at the very beginning. Radius = (1/2)x. You have to square the radius, thus you have to square 1/2 AND x. (1/2) squared = (1/4).

So ((1/2)x)^2 = (1/4)x^2

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

that is a common mistake, you're just squaring the X, and not the 1/2 before it.

ps: evga, typo on your first post.

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

evilpeta wrote:

that is a common mistake, you're just squaring the X, and not the 1/2 before it.

my teacher use to yell at us for that, i learned if (1/2x)^2 then we square both but if 1/2x^2 then the x is only square. but probably since the ^2 is part of the area formula it is assumed that it should be written (1/2x)^2

it all makes sense now T_T

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

evilpeta wrote:

that is a common mistake, you're just squaring the X, and not the 1/2 before it.

ps: evga, typo on your first post.

AHHH, oh noes where!!?

Oh, I didn't cube the x.. -.-

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

also try to rewrite 1/2x to x/2, since 1 over 2x is different from x over 2. it gets confusing sometimes

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

Well poo.. I messed that up lol. I don't like combining the fraction with the x. Was trying to keep everything separated. Meant to have parenthesis around the fraction.. so walla, I threw in some more. Think it's fixed now.

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

wasn't talking to you. lol
:oops:

looking at the first picture the "1/2x" is rather confusing without parenthesis. any math teacher or judge will see that as 1 over 2x.

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

Well I did the same thing in mine

TAKS, so you live in Texas?

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

EvGa wrote:

Well I did the same thing in mine

TAKS, so you live in Texas?

lol yes.

Brago · **Posted:** Wed Apr 29, 2009 10:31 pm

Its c.

evilpeta · **Joined:** Feb 2006 **Posts:** 895 **Location:** ...

dear God.

EvGa · **Joined:** Apr 2008 **Posts:** 2612 **Location:** Texas

ThatBluePerson wrote:

EvGa wrote:

Well I did the same thing in mine

TAKS, so you live in Texas?

lol yes.

Ahh, I miss the good ole TAKS. I think they came out with it the last year I had to take mandatory state tests. We had TAAS before that. Good stuff.

Brago wrote:

Its c.

Um, no.

Midori · **Joined:** Mar 2007 **Posts:** 3425 **Location:**

ThatBluePerson wrote:

Yeah my algebrator says that the answer is 3PIx^3 which is what I got when I first worked out the problem.

damn TAKS creators.... no there was no E.

You live in Texas? Where?

boast · **Joined:** Jan 2007 **Posts:** 477 **Location:**

evilpeta wrote:

wasn't talking to you. lol
:oops:

looking at the first picture the "1/2x" is rather confusing without parenthesis. any math teacher or judge will see that as 1 over 2x.

I thought the same as well. I was like, wtf, these choices aren't even CLOSE to the answer.

ThatBluePerson · **Joined:** Jun 2007 **Posts:** 1647 **Location:** Earth

X-Lax wrote:

ThatBluePerson wrote:

Yeah my algebrator says that the answer is 3PIx^3 which is what I got when I first worked out the problem.

damn TAKS creators.... no there was no E.

You live in Texas? Where?

Houston.

s0017 · **Posted:** Thu Apr 30, 2009 2:56 am

Heh, I took TAKS today as a Junior. I thought the sophomore test was 66 questions though, at least thats what my friend told me. O.o

_Angels · **Joined:** Nov 2007 **Posts:** 707 **Location:**

ThatBluePerson wrote:

_Angels wrote:

evilpeta wrote:

you sure the correct answer is within those options? lol
idk if im right cuz this is old stuff but the volume of a cilinder is the area of the circunference times the height. area of circunference = pi*radius^2, and height = h.
so:
r = x/2, h = 6x
V = pi*(radius)^2*height
V = pi*(x/2)^2*6x
V = pi*(x^2/4)*6x
V = (3/2)*pi*x^3

so the answer is E) none of the above. or F) this test sucks balls.

You are my new hero...

but isn't 6*1/2=3? or i'm i a math noob?

lol i have no idea ~_~ i dropped math a long time ago lol.__.
whoever can do this kinda **** is my hero , D:
im stuck at the first ;x

NuclearSilo · **Posted:** Thu Apr 30, 2009 11:43 am

pff, piece of cake. Just apply the formula

+++ · **Posted:** Fri May 01, 2009 7:47 am

NuclearSilo wrote:

pff, piece of cake. Just apply the formula

Do you see a formula there?

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