Scribe Post for April 28, 2010

Hello 9-05! Today in class we were given 3 problems. These problems were hard for some people so I will explain it to you!

1) A bag contains 36 marbles. There are one quarter as many purple marbles as red ones. There are three times as many green as purple marbles. How many green marbles in the bag?

There are 36 marbles in the bag.

so Red + Purple + Green = 36

We don't know how many red marbles there are so red will be x. There is 1/4 purple marbles out of the red ones so purple will be 1/4x. And lastly, for green, there are 3 times the number of purple marbles so green will represent 3(1/4x).

So you have to add all of those to get the number of marble in the bag.

x + 1/4x + 3(1/4x) = 36

That is your equation. Now solve for x.

So there are 18 red marbles. Now you fill in x will 18 to find out how many green marbles there are in the bag.

3(1/4x) = Number of green marbles

3(18/4) = Green

3(4.5) = Green

13.5 = green

There are 13.5 green marbles in the bag.

2) A skier takes 1.2 minutes to complete a run of 2 km. How fast in meters/second was he going?

First you must convert minutes into seconds and kilometers into meters. There are 60 sec in 1 min and there are 1000 meters in 1 km.

1.2(60)=72 sec

2(1000)=2000 m

Then you use to formula s=d/t.

He was going at a speed of 27.78 m/s.

3) A regular hexagon has 6 sides. What is the measure of one interior angle? What is the measure of all interior angles?

There are 6 triangles in a hexagon.

In an equilateral triangle the interior angles are 60 degrees.

You add them to get the interior angle of a hexagon.

60+60=120 degrees

One interior angle of a hexagon is 120 degrees.

To find them all out you multiply one angle by 6.

120(6)=720 degrees

All of the interior angles are 720 degrees.

Homework:

8.4 Text Book Work

-1-23 and 26-30

White Sheets

-All up to Age Problems

Thanks for reading please leave a comment!

Zerlina's Journal Entry

April. 5, 2010 - Interpolation and Extrapolation (Chapter 6)

Today in class I learned how to interpolate and extrapolate. I also learned the difference between them because I honestly didn't know the difference before. Interpolating is when you are given a set of values and you estimate between them.

eg.






When x=2.5 then y=?

Interpolate the given values
y=5






Extrapolating is when you estimate a value beyond a given set of values.

eg.







When y=12 then x=?

Extrapolate beyond given values by extending the line
x=8




Thanks for reading one of my journal entries. Please leave a comment!

Scribe Post for March 1, 2010

Hello 905! To day in class we went over one of our questions from our homework. Number 17.

You have to add the bottom two rectangles to get the top rectangle. Like this:

So you add each and put the simplified version on top.

(2x- 1)+(x-2)=3x+2

You combine like terms. I won't show my work because I think everybody knows how to combine like terms already. By the way if you don't know the definition of like terms here it is, Terms that only differ by their coefficient. So Terms that have the same variable and exponent.

(x+3)+(3x-2)=4x+1

(3x-2)+(x+2)=4x

Then you use these expressions to find the next rectangle on the pyramid.

(3x+2)+(4x+1)=7x+3

(4x+1)+(4x)=8x+1

And you do it one more time to find the top of the pyramid.

(7x+3)+(8x+1)=15x+4

And then your pyramid should look like this:

Now if you know how to do this you'll be able to do question 19. I'm just going to review how to subtract with algebra tiles so I don't need to go over #19.

eg. (6x+2)-(-9x+3)

You can add the opposite. So you change the minus to plus and make the numbers in the second bracket the opposite.

(6x+2)+(9x-3)

=6x+9x+2-3

=15x-1

Now here's how you do it with algebra tiles.

After that we worked on Extend, Review or the Chapter Test.

If you didn't finish it's homework

Homework:

Extend

Review of Chapter test

Journal (As always)

Stuff due on Friday: (Stash-its)

Kayaks for Rent or What Have You Got to Hide (Challenges)

Foldable

Self-Assessment

Math Links (Sheets)

Signed Test

BTW the test is on Wednesday. And for next scribe I choose Aleiah!

Please Leave a Comment and thanks for reading my scribe!

Back N' 4th

RULES



1) You spin the spinner and who ever gets the highest number goes first.



2) The opposite person of who is going first then picks a card for the person and reads out the question. If they get it right they spin the spinner and what ever they get is the number of spaces they move. If they get the question wrong they have to spin the spinner and the number they get is the number of spaces they move backward. Note: The spinner only is up to #4.

3) You will have 2 different questions. Mental Math and Long Answer questions. The mental math questions must be in your head and the Long Answer questions are done on a pad. There is a timer and you will be timed. One minute for the Mental Math Questions and three minutes for the Long Answer questions. Note: The pad and pencils will be provided.

4) No peaking at the question’s answer, THAT’S CHEATING!

5) Who ever gets to the end first wins.

Scribe Post for January 5, 2010

Hello 9-05! Today in class we went over our Check Your Understanding. Some people had a hard time to understand the difference between -2^4 and (-2)^4.

When the base is put in a bracket, everything in the bracket will be repeated depending on the exponent.

Remember this old saying? Well now it comes in handy.

When there is an even amount of negatives, the product is positive. When there is an odd amount of negatives, the product is negative.

When the base has no brackets, then you don't count the negative into the base.

Eg.

If my explanation wasn't clear enough go to Mr. Backe for help because I can't make it any more clearer than that. (Sorry)

HOMEWORK:

Workbook 3.1

Textbook: #9, 11, 13, 15, 16, 17, 18, 19, 21, 22, 23

Extra Practice 3.1 (Sheets)

Mathlink 3.1 (Colourful Sheets)

Journals (Everyday)

This stuff is due tomorrow so you better get started!

Well I guess that's it sorry if it seems short but that's all we did in class so please leave a comment and tell me how I did.

Oh yeah, I almost forgot, for next scribe I choose Melanie!

Mr.B

Hey Ralph, It's me, Zerlina! Now you hate of course.

Please come back, we miss you! I'm very sorry, and hopefully you are able to come back next year. I know your going through emotional changes, but that's life.

Math just doesn't work with out you so you have to come back. The CLASS needs you to succeed. Your an awesome teacher and we can get through this together (A message from the class). So when your back we'll be here for you.

Have a Merry Christmas and a Happy New Year!












Your best student Zerlina!

Question #20

Hello everyone! I am going to do question #20 (again) for those who didn't understand.

20) In a magic square, the sum of each row, column, and diagonal is the same. Copy and complete this magic square.

So first of all you find out the sum of the diagonal of the square.

And the sum is:

So now we know the sum, now we have to fill in the squares to make a sum of -2 1/2.

Next you have to do the easier ones first. The ones that have 2 squares filled in already.

You add up the two numbers and subtract it from -2 1/2

(-5/6)+(1/2)= -1/3

(-2 1/2)-(-1/3)= -2 1/6

1/2+(-1 1/6)= -2/3

-2 1/2-(-2/3)= -1 5/6

Then you do the same process again.

-1/2+(-2 1/6)= -2 2/3
-2 1/2-(-2 2/3)= 1/6

-1/2+(-1 5/6)= -2 1/3

-2 1/2-(-2 1/3)= -1/6

Now we have one more square to do. But you should always check your answer just in case.

We do the same thing, you could choose which numbers. You could go vertical or horizontal.

I'm going to do both ways to show that it doesn't really matter as long as you get the right answer.

1/6+(-1 1/6)= -1

-2 1/2-(-1)= -1 1/2

OR

-1/6+(-5/6)= -1
-2 1/2-(-1)= -1 1/2

I got the same answer so now we fill in the last square.

And that is how you do question #20!

Thanks for reading! Hope you enjoyed it. If you find a mistake, please comment and I'll fix it.

Question #20

Hello 9-05! I will be doing question 20, I kind of had a hard time with this so if you catch a mistake please tell me!

20) Research to find out the current price of gasoline in Calgary. It is 300 km from Calgary to Edmonton. How much less would it cast to drive this distance in a car with fuel consumption of 5.9 L/100 km than in a car with fuel consumption of 9.4 L/100 km? Give your answer in dollars, expressed to the nearest cent.

West Edmonton Mall (Taken by me)

So I put the question in bold and if you don't really understand it, it means what is the difference between the prices of gas? And difference is the answer in a subtraction question for those who don't know. So we need to find the how much the gas costs for both cars and then we have to subtract it to find the difference.

The gas price is 94.6 cents.

We need to find out how to get from 100 km to 300 km. So you can put the L and km in a fraction and multiply both by 3.

Then you have to put the gas price in a fraction over 100.

Then you multiply the L by the gas.

So now we have to find the difference.

So the difference is $9.95. So that's it and I told you I had a hard time with this and if I made a mistake please tell me and comment. Thanks for reading!

Question # 11

11. List places of situations in which surface area is important.



-When you buy a house/apartment
You would need to know how big it is so you can move into the right sized house that works for you because if you bought a house and it was too big, you would have all of this space and if you bought a house that was too small, you would need space so that's why we need surface area in a situation like this.



-When you buy furniture.
You would need to measure the surface area of your furniture so it will fit in the room and when you bring it in, you would need to fit through the door.


-When you need to plant a garden.
When you plant a garden you need to calculate the surface area of your yard so you can choose how many kinds of plants and how many plants.



-When you need fertilizer for your lawn.
You would need to calculate the grass or you might buy too much or not enough.



-When you want to buy a pool
You would need to calculate the surface area of the pool and your yard.
















-When you want to be a carpenter
You would need to calculate to surface area so you can fix an object.




-When you want to be a teacher (for math)
You would need to know how to calculate surface area so you can teach more people about it.




-When you are a scientist
You would need to if you discover something new, you would need to calculate the surface area of the new object.


-When you are an accountant
You would need to use this skill to do your job.


-When you buy a box to hold a present
You have to calculate the surface area of the present and the box too, so you know what box to buy.

-When you order a moving truck
When you are moving, you have to order a moving truck, but you need to calculate the surface area of the things, so you order the right size truck.




-When you organize a special event
You would need to calculate the surface area of the place you ordered so you can fit all of the people you have invited.



-When you buy curtains

You have to calculate the surface area of the windows.



-When you want to put a carpet in a room in your house
You have to calculate the surface area of the floor.



-When you travel
You have to calculate the surface area of your suitcase so you know how much to bring with you when you travel.



This is how big my list is! If you can make one bigger, and think of more things, go on it post it. Thanks for reading, please leave a comment.

Most Elegant Algebraic Expressions

Hello everyone! I'm sorry I couldn't go on for a few days, my Internet wasn't working properly. Finally it's working. So now I can do the posts Mr. Backe assigned us. And I can finally comment too. So anyways I am going to tell you the Most Elegant ways to find Rectangular Prisms, Triangular Prisms, the Cube, the Cylinder, and any Square Based Prism.

The Rectangular Prism:

SA=2(lw)+2(hl)+2(hw)

SA=2(6)(10)+2(4)(10)+2(4)(6)

SA=120+80+48

SA=248 square units

The Triangular Prisms:

First you find the area of a triangle.

A=bh/2

A=(4)(4)/2

A=16/b

A=8 square units

And then the base.

A=bh

A=(4)(10)

A=40 square units

And finally the roofs.

You have to find the hypotenuse by using the Pythagorean Theorem.

a squared + b squared = c squared

4 squared + 4 squared = c squared

16 + 16 = c squared

32 (square rooted) = c squared (square rooted)

5.656 = c

A=2[h(Hyp.)]

A=2[10(5.656)]

A=2(56.56)

A=113.12 square units

Then you add all of the answers together.

113.12 + 40 + 8 = 161.12 square units

I know it looks complicated but this is as elegant it's gonna get.

The Cube:

SA= 6s squared

SA= 6(3) squared

SA= 6(9)

SA= 54 units square

The Cylinder:

SA=2 pi r squared + 2 pi r h

SA=2(3.14)(3)squared + 2 (3.14)(3)(8)

SA=2(3.14)(9) + 2(3.14)(24)

SA=(3.14)18+ (3.14) 48

SA=56.52+150.72

SA=207.24

Any Square Based Prism:

You could use this if you have any Prism with a square. You could use it as a base. If you had a rectangular prism with a square on the sides than you use this formula.

Thank you for reading! Please leave a comment and tell me how I did!

Scribe Post for October 6, 2009

Hello everybody! Today in class we went over our homework from yesterday. If you didn't understand, here it is again.

We had to find the surface area of a cylinder. We were given the circumference of the circle which was 10 square units and we were also given the height which was 6 square units.

This is how you show your work.

At the end you must add the Surface Area of a Circle + Surface Area of rectangle = Surface Area of a cylinder.

We also had to glue the nets in our Journals if you haven't yet.

We worked on some new shapes. We were given the top view, the side view, and the front view. We were supposed to draw the full shape on paper.

And after that we were given a cylinder and we had to find the surface area but there was something in side of it.

Homework:

-1.2 Self-Assessment

- The How You Know You Know

-Find the Surface Area for the cylinder (up above)

-And you have to draw the shapes with all three views

-Journals

Thanks for reading, please leave a comment. For next scribe I choose Shaneille.

Why 360?

Have you ever wondered why does a circle have 360 degrees? Well I haven't really thought about it, I just went with it until the question came up in math class and then I found out.

It started out with the Babylonians and they had a base 60 number system. We use this base 60 number system in our time like 60 minutes in an hour and 60 seconds in a minute. But we have a base 10 number system. The base 60 system is called the Sexagesimal system. The Babylonians took their base and multiplied it by 6. And they came up with 360.





















360 was very close to how many days are in a year. There are actually 365.25 days in a year. The Babylonians had a calendar that consisted of 360 days a year. The Babylonians did research and watched the sky and the sun and they realized that it took at least 360 days to go though the whole process. They were very close but they thought the Sun went around the earth in 360 days. But the earth goes around the sun in 365 days.

There are 360 different sunset points of entry on the horizon during a calendar year (to the naked eye). 90 points / days between Winter Solstice to Equinox, Equinox to Summer Solstice, Summer Solstice to Equinox and then Equinox to Winter Solstice. And that is basically all 4 seasons.






















The base 60 system is also very common and is a common number too. Many numbers go into 60. Like the numbers 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 24, 30, and 60.

The numbers from the base 60 number system looks like this.

(sorry if the picture is blurry just go to this site if you cannot see)

Thanks for reading my post! I hope you understand why now! Please leave a comment.