Scribe Post for March 16, 2010

Hey guys! Welcome back from a long, long weekend. Remember that today is Tuesday not Monday. Okay, today was just basically another work period. Here's a list to prepare you for the test!

How to prepare for Thursday's Test.
Do Chapter 7 Review and Test.
Be caught up with your homework, it'll show on your test.
Do the questions that you don't exactly understand and tell Backe.

Okay, in class we went over question 10.

A square is inscribed in a circle with radius r as shown. What is the ratio of the area of the square to the area of the circle?

Okay, I can't really help you with this question because I hardly understand it at all. I didn't want to copy the answers, and pretend like I knew it. If you don't understand either, I highly recommend that you visit Backe, as I will tomorrow. But don't worry, I'll get back to this question :/

Also remember that these are due shortly :
Chapter 5 Mathlinks, Foldable, etc.
Chapter 7 Wrap it Up.
Make sure your done !

Scribe Post for January 27, 2010 !

Sorry guys if its a bit late :)

Okay so today we talked reviewed a few 4.2 questions then we talked about similar triangles. Here are the notes we took ! :



Similar Triangles

Similar=Same



Rules for Similarity

SAS- Side,Angle, Side

ASA-Angle, Side, Angle

SSS- Side,Side,Side



If a triangle has corresponding sides that are proportional, then the triangles are similar. (SSS)



If a side and another side are proportional and the angle is congruent then the triangles are similar (SAS)



If two angles are congruent and one side is proportional then the triangle are similar. (ASA)

Kinds of Triangles !

Right Angle

-one angle is 90 degrees.

Isosceles

-two sides equal

-two angles equal

Scalene

-three unequal sides



Obtuse

one angle> 90 degrees

equilateral/equilagular

-all sides equal

Homework:
4.3 Reflect and Check, Show You Know, and Check Your Understanding. Make sure you read.

I'm sorry I need to add more stuff to the scribe tomorrow, its late and the internet was off.

Mr.Backe !

Mr. Backe, how I miss you ):
I'm here like everyone else, I want to say happy holidays and a happy new year !
I really miss you, its only been a few days but the day isn't the same. Math isn't the same without you Backe either, whats math without the teacher?All I see is numbers but with you I see numbers in a different way. You showed us how to use numbers, and how they're friendly. Thanks for being a great teacher. (:

See you next year! Happy Holidays Backe !

Question 16

Hey guys ! Here is question 16(:

Boris has 2 1/2 times as much as Anna. Charlie has 3/4 as much as Anna. Anna has $ 25.60 in cash.

a) How much cash do the three people have altogether?
b) How much more cash does Boris have than Charlie?

First we have to find how much Boris and Charlie have using the information given to us. Boris has 2 1/2 times as much as Anna. So if Anna had X amount of cash, Boris would have 2 1/2 (X) amount of cash. Lets see a picture :

Okay so we know Boris has $ 64 dollars, now we have to find out how much Charlie has. " Charlie has 3/4 as much as Anna. Anna has $ 25.60 in cash." Charlie has 3/4 as much as Anna, so that would mean if Anna had x amount, he would have (3/4)x amount or x(3/4) since order of multiplication doesn't matter. Heres a picture ! (:


Now that we know what each person has, we can figure out what is the answers to A and B
a) How much cash do the three people have altogether?
So we figured out that Boris has $ 64 and that Charlie has $ 19.20 and we already know that Anna has $25.60 so we just need to add them all up! (Please don't mind all the positive signs, they are only there so the numbers meet up at the same place)
+64
+25.60
+19.20
-----------
= 108.80

- All together they have a total of $108.80 dollars !

b) How much more cash does Boris have than Charlie?
For this question we need to know how much Boris and Charlie have and subtract to find the difference. Boris has $64 and Charlie has 19.2, lets do the math.
...64
- 19.20
-----------
= 44.80

- Boris has $44.80 dollars more than Charlie.


Thanks for reading my blog. Please comment , and tell me if theres any mistakes :)

Question Number 22

Hey, here is my math question. (:

An aircraft was flying at the altitude of 2950 m. It descended for 3 minutes at 2.5 m/s and then descended for 2.5 minutes at 2.8 m/s. What was the planes altitude after the descent.

First lets see, the altitude of the plane is 2950 m.
It descended for 3 minutes at a rate of 2.5m/s
3 minutes = 180 secs at a rate of 2.5m/s
180 x 2.5 = 450 m

It then descended another 2.5 minutes for 2.8m/s
2.5 minutes = 150 secs at a rate of 2.8 m/s
150 x 2.8 = 420 m

2950
- 450
420
--------
2080 m

The plane's altitude after the descent is 2080 metres.

Heres a picture!


Please leave a comment! Thanks !

Scribe Post for November 2, 2009 !

Class 9-05 (;

Sorry if this is late, in class we talked about multiplying with decimals, and dividing with decimals.Is there a pattern, is there a rule? Why does math have to be so cruel? Just kidding, here's what we found out!

For example : (x)(x.x) = ???


Backe told us to think of a rule for this, and we came up with this :
Aleiah's rule : " When multiplying with decimals, how ever many decimal places are in the factors will be in the product " It was good, but it could be better.

So then wonderful Nicky shared his rule, " When multiplying with decimals , the sum of the decimal places in the factor will be in the product." This simply you add the decimal places, and it will be in the product! So for example 2.2 x 2.2 will be something x.xx, see how i added the 2 decimal places ?

Now on to division...
For division there isn't really a rule for dividing. You can never really know how much place holders there are going to be. After we went side-track and we talked about this !

So now you know! After we talked about subtracting and adding decimals for a bit. Heres how you do it !

HOMEWORK : Foldables the section X, and ÷
Page 57, 58, 59 Show You Know, and Check Your Understanding
Practise: Page 60, #4 or 5, 6 or 7, 8, 9, 10 , 11
Don't forget, we have a test on Thursday!!
I pick Tracey S for Scribe! I CHOOSE YOU
Please comment ! We all learn from mistakes, thanks a lot ! :)
- Thanks Backe for correcting me, much appreciated ! I couldn't really see the board.

Why 360?

Why do we use the number 360 when we refer to a circle, why not 400 or 10?
Well I did some research and found out it was the Babylonians!! The Babylonians used a system called the sexagesimal system, so instead of using the base of 10, like we do they used a base of 60.

This has many advantages as it can be divided by a lot of factors unlike 10. The base of 10 only has factors of (1,2,5,10) but 360 has factors of 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, and 360. So you now know why we use 360 degrees for a circle, but there is also other examples, like we have 60 minutes in an hour, and 60 seconds in a minute. But the most common example is the calendar. Earth's rotation around the earth is approximately 360 days (rotation over the sun)

The Babylonians had 360 days in a year, but in the present we now have 365 days (more accurate). Thats why every few hundred years, summer would line up to winter, meaning the calendar would be all messed up.
I hope you learned something and please comment!!