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## #1 2013-06-25 01:42:13

demha
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### Geometry Review

So I just need help to make sure I got my answers right and there are also a few I was not too sure on how to do them, so help with those would be great

SO numbers 1 - 4 are referring to the image. It's only numbers 1 - 3 I'm not understanding too well on how to answer them. I would appreciate help with the first one (like a walk through) to help me understand. thanks!
REVIEW:

1.
Q. Refer to the image at the right. If angle 1 is 30 degrees, and angle 5 is 70 degrees, are the two lines parallel? Explain.

A.

2.
Q. Refer to the image at right. If angle 2 is 30 degrees and angle 4 is 60 degrees, are the lines parallel? Explain.

A.

3.
Q. Refer to the image at right. If angle 2 and angle 6 are both 70 degrees, are the lines parallel? Explain.

A.

4.
Q. Refer to the image at right. If the lines are parallel, and angle 4 is 50 degrees, what is the measure of angle 6?

A. Angle 6 will be 130 degrees.

5.
Q. What is the measure of the inner angle of a regular hexagon? Show your work (and be sure to explain anything you deem necessary to make sure your work is clear.)

A. A hexagon has 6 sides.
180 x 6 = 1080
The sum of the angles of deviation is 360
SO
1080 – 360 = 720

6.
Q. What is the measure of the inner angle of a regular decagon? Show your work (and be sure to explain anything you deem necessary to make sure your work is clear.)

A. A decagon has 10 sides.
180 x 10 = 1800
The sum of the angles of deviation is 360
SO
1800 – 360 = 1440

7.
Q. Polygon A has sides of 4, 3, 5, and 3. Polygon B has sides of 8, 6, 10, and 6. What are the two possible scale factors here? Explain.

A.
To get my scale factor, I will need to divide the two polygons. This is how I will do it along with the answers for each number:
4 / 8 = 1/2
3 / 6 = 1/2
5 / 10 = 1/2
3 / 6 = 1/2

So now we know the scale factor is 1:2.

8.
Q. A triangle has angles of 34 degrees, 56 degrees, and 90 degrees. It also have sides of 6, 8, and 10. Which side is across from which angle?

A.
Side 6 will be across angle 34.
Side 8 will be across angle 56.
Side 10 will be across angle 90.

9.
Q. A triangle has one angle measuring 52 degrees, and one angle measuring 18 degrees. What is the measure of the third angle?

A. The third angle’s measurement is 110 degrees.

10.
Q. A right triangle has a 90 degree angle, and an angle x. What will the measure of the third angle be?

A. I believe the answer for this would be 90 – x.

Last edited by demha (2013-06-25 01:43:28)

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

## #2 2013-06-25 01:49:57

ShivamS
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### Re: Geometry Review

1. No, as 1 should = 5 if they are parallel and had a transversel through them.

2. Also no, as co-interior angles are supplementary and thus 6+4 should = 180. 30 and 60 obviously are complementary, not supplementary.

3. Yes.

4. They are co-interior and thus supplementary. therefore, 50+x=180 and x=130. This, angle 6 is 130 degrees.

5. A bit of confusion. Do you mean to ask how much is each interior angle? If yes, the sum of interior angles in a regular polygon are the # of triangles 8 180 or (n-2)*180. 4*180 = 720 degrees. That is the sum of interior angles. each one is 720/n = 120 degrees.

6. Same concept as 5. 8*180 = 1440. Divide that by 10 and it is 144.

I have discovered a truly marvellous signature, which this margin is too narrow to contain. -Fermat
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world. -Archimedes
Young man, in mathematics you don't understand things. You just get used to them. - Neumann

## #3 2013-06-25 02:10:50

bob bundy
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### Re: Geometry Review

hi demha

Have a look back to

http://www.mathisfunforum.com/viewtopic.php?id=19401

post 6.

When you have parallel lines the four acute angles are all the same and similarly the four obtuse ones are the same.

That should help with Q 1 2 and 3.

7.
Q. Polygon A has sides of 4, 3, 5, and 3. Polygon B has sides of 8, 6, 10, and 6. What are the two possible scale factors here? Explain.

A.
To get my scale factor, I will need to divide the two polygons. This is how I will do it along with the answers for each number:
4 / 8 = 1/2
3 / 6 = 1/2
5 / 10 = 1/2
3 / 6 = 1/2

So now we know the scale factor is 1:2.

That's good but the question says two possible scale factors.  You've given the small to large so the other will be ???

8.
Q. A triangle has angles of 34 degrees, 56 degrees, and 90 degrees. It also have sides of 6, 8, and 10. Which side is across from which angle?

A.
Side 6 will be across angle 34.
Side 8 will be across angle 56.
Side 10 will be across angle 90.

Correct

9.
Q. A triangle has one angle measuring 52 degrees, and one angle measuring 18 degrees. What is the measure of the third angle?

A. The third angle’s measurement is 110 degrees.

Correct

10.
Q. A right triangle has a 90 degree angle, and an angle x. What will the measure of the third angle be?

A. I believe the answer for this would be 90 – x.

Correct

Bob

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

## #4 2013-06-25 02:15:41

ShivamS
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### Re: Geometry Review

Is this the compuhigh stuff again?

I have discovered a truly marvellous signature, which this margin is too narrow to contain. -Fermat
Give me a lever long enough and a fulcrum on which to place it, and I shall move the world. -Archimedes
Young man, in mathematics you don't understand things. You just get used to them. - Neumann

## #5 2013-06-25 03:19:40

bob bundy
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### Re: Geometry Review

#### Shivamcoder3013 wrote:

Is this the compuhigh stuff again?

Looks like it.

Bob

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

## #6 2013-06-25 08:33:05

demha
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### Re: Geometry Review

7.
Would it be 2:1?

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

## #7 2013-06-25 09:07:48

anonimnystefy
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### Re: Geometry Review

Yup!

The limit operator is just an excuse for doing something you know you can't.
“It's the subject that nobody knows anything about that we can all talk about!” ― Richard Feynman
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

## #8 2013-06-26 04:55:33

demha
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### Re: Geometry Review

Thanks guys!

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