Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

hi demha,

Q16 and Q19 are correct.

I'm getting a different answer for Q17.

Q18. The hypotenuse is 12 and we want the adjacent. So

Q20.

Work out the area of the square.

Work out the area of the triangle.

Subtract to get the shaded area.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

#17 - so it would be 3 x volume DEVIDED by what pie x height equals?

#18 - So it would be 12 x .42 = 5.04

Assuming that A means area, how would I use the area to get the height?

---

#20 - Area of the entire square is 144. The inner triangle I used this equation I found online. Tell me if it's right or wrong (or maybe if I am doing it wrong):

A = 1/2 x (a) x (b) x sin(C)

A = 1/2 x (12) x (6) x sin(60)

A = 1/2 x (72) x sin(60)

A = 36 x sin(60)

A = 36 x .86

A = 30.96

*Last edited by demha (2013-10-01 12:20:36)*

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

hi demha

#17 - so it would be 3 x volume DEVIDED by what pie x height equals?

Correct. That will give you r squared.

#18 - So it would be 12 x .42 = 5.04

Assuming that A means area, how would I use the area to get the height?

No A stands for Adjacent. I'm using SOHCAHTOA. I assume you know what that is. So 5.04 is the answer.

---#20 - Area of the entire square is 144. The inner triangle I used this equation I found online. Tell me if it's right or wrong (or maybe if I am doing it wrong):

A = 1/2 x (a) x (b) x sin(C)

A = 1/2 x (12) x (6) x sin(60)

A = 1/2 x (72) x sin(60)

A = 36 x sin(60)

A = 36 x .86

A = 30.96You can use this formula and that answer is what I got (except I had more decimal places). But you didn't need to because they have given you the base (= 6) and the height (= 6root3) for the triangle.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

#17 - I got 16.01. Squared it to get 4.00. So answer is 'A'.

#18 - So 5.04 is the answer, I would have to round it up to 5 to get 'A'?

---

#20 - So 144 - 30.96 = 113.04. Where would I move on from here?

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

Yes. Those two are now correct.

Q20. The possible answers have a root 3 in them. sin60 is root3 divided by 2.

You'll have to rework the question leaving the root 3 in your answer, rather than putting a decimal.

OR.

Take their answers, and work out the decimal answer on a calculator to find which answer matches yours.

Bob

You cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

I decided to go with your second opinion. I used 'B':

144 - 18 (sqrt 3)

144 - 31.1769

112.8230

That's the closest I got. Am I doing the equation correctly?

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

112 is what I got. When you used 0.86 for sin(60) you lost some accuracy. A more exact value is 0.86**602540378443**......

As you see your value was lower and after multiplying by 36 the amount that you subtracted was about 1 less then it should have been. This accounts for a larger answer when you did the calculation in the earlier post. But it's close enough for you to choose the right letter.

My advice for the future is that you keep accuracy during any calculation, only rounding off at the very end. That way you won't get an answer that is so far from the required answer.

Here's my way of doing this question:

area of square = 12 x 12 = 144

area of triangle = half base x height = 3 x 6√3 = 18√3

area shaded = 144 - 18√3

Bob

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

Wow... that was so simple. Thank you for your help! I submitted the lesson and got ONE wrong. It was #8. Let me bring it up again:

demha wrote:

After some time we agreed that measure B was greater than measure A, so the answer would be 'B'. But it was marked wrong. I know angle A is NOT bigger than angle B, and they are both definitely no equal, so I thought maybe the correct answer would be 'D'?

*Last edited by demha (2013-10-02 08:06:54)*

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

hi demha,

Oh how unfortunate. I think that shows why multi-choice can be so unfair. You do all that correct mathematics but have no chance to show your teacher what you did. I suppose it will have to be D; you did do extra calculations after all. But it's a poor question because I could tell just by looking. 11 and 9 are sufficiently close in size for me to argue that it is obvious that the third side is much smaller. I don't need to complete the calculation 121 - 81 to be able to tell that's less than 81. Oh well, it's happened; so submit D and you should get it correct.

Bob

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

I sent in the revision and 'D' was correct. Got a 10.000 on the lesson and now my Geometry course is finished. I would love to thank you, Bobbym and anonimnystefy for your help. It was and still is highly appreciated!

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

You are welcome. It's been a pleasure helping you. Well done for the high marks. Any more maths courses to come ?

Bob

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

Well I might be switching schools. But if I do need help, I will surely be back here! This is an awesome place with awesome people!

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

demha wrote:

Well I might be switching schools.

Good idea. I will happily give an evaluation of any you are looking at if you provide a link.

Bob

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

Well I might be enrolling into K12 (http://www.k12.com/). I have heard quite a few great things about it and I know a few friends who have been doing K12. It seems pretty good since I will be able to actually talk to my teachers if I need help or have any questions.

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

Hi demha,

I've had a look but got stuck over one issue. Here's what I've seen:

The tuition is MUCH, MUCH better than what you have had with Compu. The pages are nicely laid out with good use of text, pictures and color. There are some excellent interactive tasks which are marked as you go so if you're making a mistake you find out straight away rather than after you have done 20 questions. I looked at the demos for the quadratic formula, circles and symmetry. All made very good use of the computer with clear step by step instructions. I did get a couple of 'missing file' errors; that may be because I'm not enrolled and so lack the right software to use the course properly. I think it's unlikely there are errors at their end. They make use of Geogebra!

The videos show that the teachers actively engage with the students to help with the work.

I could not however find out anything about certification / graduation / a diploma. They don't seem to say how a student's achievements are assessed at all. So I tried a 'chat' session and was directed to a video about the school. But still nothing on assessment.

So I tried a second chat session. I got timed out before I'd even typed my query.

So I tried a third time. The person I chatted to this time would not reveal anything about this. I had explained that I am not the student so she wanted to know what state you are in. I had to explain that I don't know that; or even if you live in the US. All she could suggest is that you make the enquiry yourself. I am at a loss to understand why something so basic is such a secret.

Maybe your friends can answer this. Or you'll have to have your own 'chat' session.

Why do I think assessment is so important?

In the UK you cannot get a certificate (eg. GCSE or A level) without attending an exam centre and sitting an exam. The assessment is fully supervised so that the chance of 'cheating' is minimal. As a result the qualification obtained is valued by colleges, universities and employers. I was amazed that for Compu you can get a diploma just by submitting multi-choice answers over the internet. I know you have worked diligently to master the work but what is to stop a student from just asking someone else to answer the questions for them. And the worksheets are the same for each student so once a set of questions has become public, someone could set up in business providing answers for a price.

So I think it's important to know: (i) how will I be assessed? (ii) What will I get if I reach the required standard? (iii) What value will this have in the world of further education and employment?

I hope these comments are of use to you. Let me know what happens next.

Bob

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

Thank you very much for looking into this Bob! I've heard and read a lot of great things about K12. One of my friends who was in K12 did not finish the high school program. Instead, he transferred to another private school which was supposed to be better.

After some web surfing, I came upon this page on K12:

http://www.k12.com/take-a-peek/college-acceptances#.UlC1koZmiSo

It's a list of the many colleges/universities that students who graduated from K12 were accepted into. I am familiar with on of the colleges, B.U. (Boston University). I know someone who had gone there and it's supposed to be one of the top colleges in the U.S. So from this page, I guess students do graduate with some kind of certificate or diploma!

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

hi demha,

In the UK, a student who wants to get to a college or university will usually do exams known as A levels. (There are ways for a student who has other qualifications to demonstrate the 'right' abilities ... I am talking about the majority). There are government approved exam boards and an organisation called the Joint Council for Qualifications. Together, these organisations set the standards and the exams. Mostly, students sit the exams at a school or other recognised centre. A certificate can also be shown to a prospective employer.

I am not familiar with how the system works in the US. I had hoped to learn something of this from K12. I'm surprised that they haven't got a page that tells a prospective student what qualifications the study is leading to, and how they will be tested to show they have reached the standard. Maybe you already know the answers to these questions in which case all may be fine. Perhaps there are so many possible qualifications so they find it impossible to answer my questions simply.

My advice to you is this:

(i) Have a clear idea what you are aiming for so you can develop a clear route to your goal.

(ii) Contact K12 and tell them where you live, what qualifications you have already, and where you are aiming for so they can advise you of the best course for you.

If you get satisfactory answers then the school may be the right one for you. I'd be interested in knowing what they say because it will improve my understanding of the education system in the US.

Good luck!

Bob

Offline

**anonimnystefy****Real Member**- From: The Foundation
- Registered: 2011-05-23
- Posts: 15,918

demha wrote:

I sent in the revision and 'D' was correct. Got a 10.000 on the lesson and now my Geometry course is finished. I would love to thank you, Bobbym and anonimnystefy for your help. It was and still is highly appreciated!

Hi demha

That is fantastic! I'm glad I could help a bit.

And good luck with switching. I sure hope K12 will be better for you than Compu.

Here lies the reader who will never open this book. He is forever dead.

Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and Punishment

The knowledge of some things as a function of age is a delta function.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 93,819

Hi demha;

Congratulations, well done!

**In mathematics, you don't understand things. You just get used to them.**

**I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.**

Offline

**demha****Member**- Registered: 2012-11-25
- Posts: 195

Hi bobbym and anonimnystefy , thank you very much!

And Bob, from what I have heard, AFTER I am done with my high schooling program, I am going to have to take a SAT test which basically is there to help any college I am trying to get into understand what points I may be weak in (points as in subjects such as math, English, history, etc.). Now I was also recommended by the school to take certain courses from my local community college which would add to my credits and will allow me to get into a better college (not exactly sure how it may be in the UK, but in the US you need 22 credits to get into a college, each course will give you different amounts of credits, any where from 0.5 - 1.00).

So my plan is to get as many credits I can which could help me get into a good college. I have had two colleges in mind that are not too far from where I am and I know some people who have gone there, so from what they have said these colleges seem to be pretty good.

As for contacting K12, I have already done so some few weeks ago and am waiting for their reply to see if I qualify for their schooling program.

Once again, I just really want to thank you all for your help! It would have been super hard for me to finish my Algebra and Geometry but, with you guys, it's been a smooth road!

"The thing about quotes on the Internet is you cannot confirm their validity"

~Abraham Lincoln

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 6,873

hi demha,

Thanks for the explanation. Sounds like you've got it well planned. Good luck!

Bob

Offline