Math Is Fun Forum

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Alright how about #8?

8. When the rope goes around the barn the other way, what is the new radius? How much of a circle can it make without hitting the barn or overlapping area you've already found? What is that area?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

Hold on, we are still on 7. What do you get now for the area in red there?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Oh oh!
area = pi * r^2
area = pi * 30^2

area = 2827.433

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

The area that is colored in red is only 1 / 4 of that.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

OH! So
area = (1/4) * pi * 30^2
= 706.858 (How much is that in pi)

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

You do not have to convert to decimal. Just do this,

(1/4) x 900 x pi = 225 pi

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Oh oh alright. Okay 225 pi is my answer.
Onto #8?

8. When the rope goes around the barn the other way, what is the new radius? How much of a circle can it make without hitting the barn or overlapping area you've already found? What is that area?

---

I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

The same answer as 7 and use the same drawing except the shaded area is on the bottom.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

So answer for 8 is (1/4) x 900 x pi = 225 pi as well?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

Yes, I believe so.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Okay. How about number 9 now?

9. The areas you found in 7 and 8 overlap each other. How much do they overlap? What *approximate* shape do they make? What is that area?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

I would say about 90 because it is slightly less than a 10 x 10 square.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Okay so the shape is approximately a square. What is its area?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

It is slightly less than 10 x 10 = 100, So I am approximating 90. This is what they want for the question, an approximate area. To do better requires more mathematics.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Okay that answers the area and the shape. But at the beginning of the question they ask by how much do they overlap.?

---

I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

And after that could you also help me with number 10:

10. What is the total grazing area the goat can reach?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

That is by how much they overlap. Anymore than that I do not know.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Alright, let's move to 10?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

10 requires calculus for an exact answer. The best that can be done without it is an approximate answer.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

An approximate answer is fine, how can I solve it?

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

The area is everything but twice the red area.

An approximation has already been done by zee-f who passed this question as

(3/4 * 50^2 * Pi)+ (1/4 * 30² * Pi) + (1/4 * 30² * Pi) - 90
= 7214.2020292

which you will round to 7214. This is very close to the exact answer.

Notice that the goat became a cow!

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Alright, thank you very much!
Thank you so much for your help. There's a lesson I'm gonna need help with tomorrow. I'll tell you when i submit the topic.
Thanks again!

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Areas Review

Did you check if those answers cleared?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

Yes! They were all correct. Thank you so much again

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters

rogerwaters

Member

Registered: 2013-11-02

Posts: 85

Re: Areas Review

I have posted the new lesson I needed help with.
I named it "Surface Area and Volume of Spheres, Cylinders, and Cones"
Thanks again!

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I think there are things in my story that have helped my creativity. Your father being killed, for instance, is one of the best things that could happen to a kid if he's going to write poetry or songs.
-Roger Waters