help area of shaded region

- anonymous

help area of shaded region

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- anonymous

@

##### 1 Attachment

- geerky42

Can you find area of semicircle?

- geerky42

Semicircle is just half the circle.
So it's like finding area of circle, but THEN you divide it by 2.

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## More answers

- anonymous

yes that 4.71cm2

- anonymous

@geerky42

- anonymous

was that right @geerky42 ?

- anonymous

@Michele_Laino

- geerky42

No.

- geerky42

Area of circle is \(A = \pi r^2\)
So to find area of semicircle, you just use this formula then divide by 2.

- anonymous

but you said semi circle so wouldn't it be A=1/2pi r

- geerky42

My point is, to find semicircle, you just find area of circle, then divide by 2. Get it?
Also it's \(\pi r^2\), not just \(\pi r\).

- geerky42

So area of semicircle is \(\dfrac{\pi r^2}{2}\)

- anonymous

@geerky42 so 9.42cm2/2=4.71cm2

- geerky42

Radius is 3, so you have \(\dfrac{\pi(3)^2}{2} = \dfrac{9\pi}{2}\approx 14.137\)

- geerky42

Just remember that \(\pi\approx3.14\)

- anonymous

yes you told me that, thats how remember what pi is but how did you get the 9pi over 2

- geerky42

\(3^2 = 9\)

- geerky42

you divide 2 because semicircle

- geerky42

Is that clear?

- anonymous

yes kinda

- anonymous

thank you though @geerky42

- geerky42

Well, we are not done

- geerky42

we got area of semicircle. Now we need to subtract that by area of triangle

- geerky42

(Area of semicircle) - (Area of triangle)
Right?

- anonymous

yea

- geerky42

Ok. Area of triangle is \(\dfrac{1}{2}bh\)
Do you know base and height here?

- anonymous

but we don't have the area of the triangle so we need to solve for the triangle

- geerky42

Right.

- anonymous

so 3 would be our height

- anonymous

so how would you find the base given only the height

- geerky42

We don't really have to use height to find base.
Triangle and semicircle share same base, right?

- anonymous

yes

- anonymous

do the MAGIC! drawing thing geerky

- geerky42

We know that radius of semicircle is 3, so what is diameter?

- anonymous

:D

- anonymous

hahaaaa @camacho01erick that was the best response

- geerky42

lol. though I don't see the need to drawing something here lol.

- anonymous

1.5

- geerky42

maybe I will do magic thing once asker solve something like gif of victory lol.

- geerky42

@Mromanos96 No
\(d = 2r\), right?

- anonymous

k

- anonymous

yes

- anonymous

6

- geerky42

|dw:1433962650107:dw|

- anonymous

:0

- geerky42

Yeah so diameter is 6.
Therefore base of triangle is 6.
MAke sense so far?

- anonymous

yes so next we have 1/2 6*3

- geerky42

|dw:1433962764011:dw|

- geerky42

Sorry yesh that's correct.

- anonymous

lol funny ones

- geerky42

just laughing at ":0"

- anonymous

so thats 3/64 @geerky42 great gif btw

- anonymous

that kinda scares me

- anonymous

@camacho01erick it kinda does if you look at it for a little

- anonymous

ikr

- geerky42

|dw:1433962900186:dw|

- anonymous

how do you do that :D

- anonymous

:0 my favorite show man

- anonymous

@camacho01erick he's a wizard

- anonymous

fa fa fabulas

- geerky42

Anyway, no I got 9 for area of triangle

- geerky42

\(\dfrac{1}{2}*3*6 = 3*3 = 9\)

- geerky42

Right? @Mromanos96

- anonymous

how didi you do the gif @geerky42

- anonymous

ah how did you get that the only other one i got is a decimal

- geerky42

For area of triangle?

- geerky42

Did you use calculator?

- geerky42

I guess I need to make tutorial @camacho01erick in LaTeX section. I will tag you someday, I promise.

- anonymous

kk

- anonymous

yea

- anonymous

good thing i fanned you @geerky42

- geerky42

Well, put that in calculator 1/2 * 3 * 6

- geerky42

You should get 9, right?

- geerky42

lol @camacho01erick

- anonymous

yup

- anonymous

|dw:1433963336155:dw|

- anonymous

so 9cm^2

- geerky42

OK.
Now do final thing;
(Area of semicircle) - (Area of triangle)

- geerky42

We have \(14.137 - 9\)

- anonymous

we are /\tlas we will follow and we will not forget and will not forgive

- anonymous

5.137

- geerky42

Yep.
Sorry first area should be \(14.13\) since we have to use \(3.14\) for pi.
But anyways your final answer is \(\boxed{5.13~\text{cm}^2}\)

- geerky42

Is that clear so far?

- anonymous

yes crystal

- geerky42

ok good.

- anonymous

@geerky42 one last question

##### 1 Attachment

- geerky42

https://www.mathsisfun.com/data/relative-frequency.html

- geerky42

And here, voting registration status is irrelevant.

- geerky42

So we just need to find how many adult prefer newspapers
Then divide it by 252 (total)

- geerky42

Follow me so far?

- anonymous

yes

- geerky42

OK. how nay adults prefer newspaper?

- geerky42

how many*

- anonymous

46+24=70

- anonymous

hi

- anonymous

70 /252= 0.2

- geerky42

Correct.
So relative frequency is \(\dfrac{70}{252}=?\)

- geerky42

yeah but close. question said at least two decimal places.

- geerky42

So we have 70/252 = 2.777777777...
So round that to .28

- anonymous

0.27

- geerky42

That's your answer.

- anonymous

so it .28 not 0.28

- anonymous

|dw:1433964202516:dw|

- geerky42

Well it is closer to .28 than .27

- geerky42

0.28 and .28 are same

- anonymous

true

- anonymous

so really .28 or 0.28 because ales is very specific on it

- geerky42

I would go with 0.28

- anonymous

ok @geerky42 last one promise

##### 1 Attachment

- geerky42

|dw:1433964384649:dw|

- geerky42

sorry no need to use graph

- geerky42

But here, "input" is time spending in texting.
Here, you have x = 4
So plug that into best fit line \(y = -0.73x+8.53\)

- anonymous

5.61

- geerky42

\[y = -0.73(\bf\color{blue}4)+8.53\]

- geerky42

yeah 5.61 is your answer.

- anonymous

##### 1 Attachment

- anonymous

alright man thanks so much @geerky42

- geerky42

No problem

- anonymous

and um how do you do those gifs lol

- geerky42

|dw:1433964611059:dw|

- geerky42

I will make tutorial of it by tonight. Check tomorrow.

- anonymous

but how on drawing????

- geerky42

I will make tutorial later, I promise. Check tomorrow.

- geerky42

It's little complicated.

- anonymous

ok message us tommorow

- geerky42

I will tag. You want message anyway?

- anonymous

sure

- geerky42

What about you? Or nah? @Mromanos96

- anonymous

yeah tag me also

- geerky42

ok I will tag both you

- anonymous

geerky is a new moderator lol

- geerky42

I wish lol.

- anonymous

but how can you be a moderator anyways

- anonymous

a beginner have done it

- geerky42

You got to apply somewhere... I don't know because I was planning on doing that anyway lol.

- anonymous

|dw:1433964783733:dw|

- geerky42

You can ask that on OpenStudy feedback.

- anonymous

lol he'd be the number one

- geerky42

I wasn't planning*

- anonymous

i copyed yours lol

- geerky42

I can see that ;)

- anonymous

lol

- anonymous

we are /\tlas we will follow we will not forget and we will not forgive

- anonymous

bye

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