Help with geometry.

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Mr. Beefy0 Apr 24, 2012

The measure of a central angle of a sector of a circle is 90degrees. The arc length of the sector is 4pi cm. What is the radius of the circle?

I have been trying for a good 30 minutes on this fucking problem and have come nothing close to the answer. I know the radius is 8 because it was on an example question from yesterday, but I do not remember how to get it. I am asking for the steps to get the answer.
ㄎңձժø൰ (YW)🔫🔴🌆 Apr 24, 2012

4pi times 4 to get full diameter, then divide by 2pi o get radius.

4pi --> 16pi --> 8
Mr. Beefy0 Apr 24, 2012

⛄🔥aժժ⛄ʗℌɪℒℒყ🔥⛄ wrote:
4pi times 4 to get full diameter, then divide by 2pi o get radius.

4pi --> 16pi --> 8

I kinda understand that. But I'm so used to a totally different way.
Can you explain it using this formula?

(arc/360) * 2pi r = x
muddybruin Apr 24, 2012

Substitue arc=90 degrees
Substitute x=4*pi
Solve for r
You get r=8 if you do everything right
Mr. Beefy0 Apr 24, 2012

muddybruin wrote:
Substitue arc=90 degrees
Substitute x=4*pi
Solve for r
You get r=8 if you do everything right

I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi! Sorry for seeming like an ass but I have a test over this but I do not understand it just isn't clicking.
Carpenter Apr 24, 2012

Mr. Beefy0 wrote:
muddybruin wrote:
Substitue arc=90 degrees
Substitute x=4*pi
Solve for r
You get r=8 if you do everything right

I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi! Sorry for seeming like an ass but I have a test over this but I do not understand it just isn't clicking.
(90/360)2pi(r)=4pi
It really doesn't get much simpler.
Mr. Beefy0 Apr 24, 2012

🍀💀ᏫPᏌᎦ💀🍀 wrote:
Mr. Beefy0 wrote:
muddybruin wrote:
Substitue arc=90 degrees
Substitute x=4*pi
Solve for r
You get r=8 if you do everything right

Snipped
You have a test over this and instead of asking your teacher to meet up with ya after school or during lunch you come on a game forum. And to top it off you act like an ass. you're a real road scholar aren't ya. You deserve to fail. Sorry if I seem like an ass but I don't get morons that do stupid shit like this.
Jesus Christ, when the fuck did every detAil of my life have to play a role in this? If you would like to know why I didn't stay after it's because she doesn't fucking stay after. The reason I'm angry is because I have been out sick and came back today to get this sht of which I do not understand
💀De͜sтяоγe͜я💀 Apr 24, 2012

🍀💀ᏫPᏌᎦ💀🍀 wrote:
Mr. Beefy0 wrote:
muddybruin wrote: ✂
I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi
You have a test over this and instead of asking your teacher to meet up with ya after school or during lunch you come on a game forum. And to top it off you act like an ass. you're a real road scholar aren't ya. You deserve to fail. Sorry if I seem like an ass but I don't get morons that do stupid shit like this.
The arc is 1/4 of the circle, because the center a a rite angle, so this goes 4 times into a full circle (4pi * 4=16pi)
Then to get the diameter you divide this by pi (16pi/pi= 16)
Then to get the radius you divide the diameter by 2 (16/2=8)
How old are you exactualy?
Mr. Beefy0 Apr 24, 2012

I kinda understand now. Here is how I got it

4/ (90/360) = 16

16/2 = 8

I apologize i did not understand that, but anything to do wit circles is confusing because the formulas are similar.
ADD WEC Apr 24, 2012

Cheater!!do ur homework by urself!!
whette fartze Apr 24, 2012

1+1 is 1 on a bun.
TheNewfieBullet Apr 24, 2012

(90/360)2pi(r)=4pi
(1/4)(2)(PI)(r)=4pi
(1/2)pi(r)=4pi
Divide both sides by PI
0.5r=4
Divide both sides by 1/2
r=8
Mr. Beefy0 Apr 24, 2012

the destroyer 3 wrote:
🍀💀ᏫPᏌᎦ💀🍀 wrote:
Mr. Beefy0 wrote:
muddybruin wrote: ✂
I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi
Snipped because you are a douche ✂
The arc is 1/4 of the circle, because the center a a rite angle, so this goes 4 times into a full circle (4pi * 4=16pi)
Then to get the diameter you divide this by pi (16pi/pi= 16)
Then to get the radius you divide the diameter by 2 (16/2=8)
How old are you exactualy?
I am 17 taking geometry because I didn't take it my sophomore year. Anyway, thaw similar to the thought process I had.
💀De͜sтяоγe͜я💀 Apr 24, 2012

of above

To get from radius to diameter you multiply by 2

to get from diameter to circumference you multiply by pi

To get from circumference to 1/4 circumference you divide by 4

So to work this backwards, start at the last step and do the opposite (* instead of /, / instead of *, + instead of -, - instead of +)
💀De͜sтяоγe͜я💀 Apr 24, 2012

Mr. Beefy0 wrote:
the destroyer 3 wrote:
🍀💀ᏫPᏌᎦ💀🍀 wrote:
Mr. Beefy0 wrote:
muddybruin wrote: ✂
I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi
Snipped because you are a douche ✂
The arc is 1/4 of the circle, because the center a a rite angle, so this goes 4 times into a full circle (4pi * 4=16pi)
Then to get the diameter you divide this by pi (16pi/pi= 16)
Then to get the radius you divide the diameter by 2 (16/2=8)
How old are you exactualy?
I am 17 taking geometry because I didn't take it my sophomore year. Anyway, thaw similar to the thought process I had.
I'm 10, rofl(ysst)
Mr. Beefy0 Apr 24, 2012

the destroyer 3 wrote:
of above

To get from radius to diameter you multiply by 2

to get from diameter to circumference you multiply by pi

To get from circumference to 1/4 circumference you divide by 4

So to work this backwards, start at the last step and do the opposite (* instead of /, / instead of *, + instead of -, - instead of +)

Thank you, this makes more sense. I have never been good at working circles backwards, only triangles because they are easy.
💀De͜sтяоγe͜я💀 Apr 24, 2012

Lol, I'm still 7 years below you, and doing your HW for you, any other mathes whilst I'm on a roll?
Mr. Beefy0 Apr 24, 2012

the destroyer 3 wrote:
Lol, I'm still 7 years below you, and doing your HW for you, any other mathes whilst I'm on a roll?

Holy shit, you are only 10? Not right now lol I'll pm you if I need help. Honestly your explanation is the only that made sense to me even though the others were explaining it correctly.
TheNewfieBullet Apr 24, 2012

Mr. Beefy0 wrote:
the destroyer 3 wrote:
Lol, I'm still 7 years below you, and doing your HW for you, any other mathes whilst I'm on a roll?

Holy shit, you are only 10? Not right now lol I'll pm you if I need help. Honestly your explanation is the only that made sense to me even though the others were explaining it correctly.
I wouldn't believe that he is ten. I call bullshit.
💀De͜sтяоγe͜я💀 Apr 24, 2012

Well, mathes has always been my strong subject.
dr p Apr 24, 2012

Wow, how come you are only learning this shit at 17?? At my school they taught basic geometry in 1st year (11 years old)
vinnie the deal Apr 24, 2012

🍀💀ᏫPᏌᎦ💀🍀 wrote:
Mr. Beefy0 wrote:
muddybruin wrote:
Substitue arc=90 degrees
Substitute x=4*pi
Solve for r
You get r=8 if everything right

I know the answer is 8, but how the fuck do. Get there? What ar the steps? I don't know how to work a formula backwards when thisshit is in terms of pi! Sorry for seeming like an ass but I have a test over this but I do not understand it just isn't clicking.
You have a test over this and instead of asking your teacher to meet up with ya after school or during lunch you come on a game forum. And to top it off you act like an ass. you're a real road scholar aren't ya. You deserve to fail. Sorry if I seem like an ass but I don't get morons that do stupid shit like this.
It is, Rhodes Scholar. Try to make sure that you don't make yourself look stupid while trying to insult someone else's intelligence.
Mr. Beefy0 Apr 24, 2012

dr p wrote:
Wow, how come you are only learning this shit at 17?? At my school they taught basic geometry in 1st year (11 years old)

All schools are different mate. My brothe learned this for the first time in collage years ago. Times are changing because america has a low iq
dr p Apr 24, 2012

Mr. Beefy0 wrote:
dr p wrote:
Wow, how come you are only learning this shit at 17?? At my school they taught basic geometry in 1st year (11 years old)

All schools are different mate. My brothe learned this for the first time in collage years ago. Times are changing because america has a low iq
Yeah, kids playing games and chatting in fora instead of concentrating on their studies...
Mr. Beefy0 Apr 24, 2012

dr p wrote:
Mr. Beefy0 wrote:
dr p wrote:
Wow, how come you are only learning this shit at 17?? At my school they taught basic geometry in 1st year (11 years old)

All schools are different mate. My brothe learned this for the first time in collage years ago. Times are changing because america has a low iq
Yeah, kids playing games and chatting in fora instead of concentrating on their studies...
Implying I am at school. Actually no I am not, I'm sitting here doing my homework allowing myself 1 forum post for every 2 questions. Don't insult my intelligence.