Tuesday, January 26, 2010
Use mental math to determine each of the following.
300% of 2000
you have to fid 100% 100%=2000
to get 300% you multiply by 3 so you have to multiply 2000 by 3
100% multiplied by 3 = 300%
2000 multiplied by 3 =6000
so 300% of 2000 is 6000
Q1) Explain how you could use mental math to find each of the following:
a. 300% of 40. b. 0.5% of 120. c. 10.5% of 80.
I use a ratio table to get my answer usually. In this one I went straight to multiplying 100% to 300% because it is an easy number to find. Then i multiply 40 by 3.
You can make the number a decimal by dividing it by 100. Then i multiplied the percent by 10, so its an easier number to work with. I took 1.2 then multiplied it by 5 which makes 6. And last divided it back down by 10.
I took a long way, but if you use numbers you work good with then it still works. I made 10% by dividing 100 by 10. Then I made 0.5% by dividing 1% by 2 and added 10% and 0.5% together to make 10.5%.
Q2) Describe 2 ways to find 6% of 129.
one way is that you can go from 100 to 1(on a ratio table). Then multiply 1 by 5 to get 5 and add the 5% and 1% together to get 6%.
--Or you can divide 120 by 100% to get 1.2. Then multiply 1.2 with 6% which gives you 7.2.
Mr. Harbeck gave us this extra question.
Q3) How do you find 10%, 1%, 25%, 5%, 150%, and 0.5%?
- 10%= 100/10.
- 1%= 100/100.
- 25%= 100/4 OR 100/2=50, then 50/2=25.
- 5%= 100/10=10, then 10/2=5.
- 150%= 100/2=50, then 50+100=150.
- 0.5%= 100/100=1, then 1/2=0.5.
Thanx for reading!!!!
Pleaze leave comments!!!! =) =D =]
Tuesday, January 19, 2010
to help you solve this problem.. you have to represent the part and the total..
a.) 75km/50km=1.5X100=150 km
thanks for reading!
please comment if i got it wrong..
to find the questions go to www.mytextbook.ca
Monday, January 18, 2010
We went over the 3 show you knows in the book.
We learned about how we can get fractions from percents(percents are fractions out of 100 that can be simplified), percents from decimals (multiply the decimal by 100) and decimals from fractions (divide the numerator by the denominator ) .
After we went over these questions, we had to copy the key ideas in the 4.2 Fractions, Decimals, Percents section of our foldable
This is what we had to write:
After we finished copying the key ideas section in our foldable, we had to do the first 6 questions in our textbook. You can find these questions at mytextbook.ca
Here is a video to help you understand more about percents:
I hope that you found my scribepost somewhat helpful to you.
4. Convert each fraction to a decimal and
( click image )
5. Rewrite each fraction as a decimal and
( click image )
6. Convert each decimal to a percent and
( click image )
THANKS FOR LOOKING AT MY BLOG !
PLEASE COMMENT !
Thursday, January 14, 2010
14. a) If 200 squares were used instead of 100 squares to represent 100%, how would you show 0.25%?
b) If 400 squares were used instead of 100 squares to represent 100%, how would you show 0.75%?
(My scanner stoped working after that last scan so i just took this picture from mytextbook.ca)
a) If we used 200 squares instead of 100 we would need to double the numerator because the denominator (100) was doubled so when representing what would normally appear as 1/4 would now appear as 1/2 but still be equal to 1/4.
b) If we used 400 squares instead of 100 we would need to quadruple the numerator because the denominator (100) was quadrupled so when representing what would normally appear as 3/4 would now appear as 3 but still be equal to 3/4.
And that was my (slightly late) scribepost I hope it was informative.
I think she meant was an example like this: (sorry no pic)
Shindi meant was that on a graph pretend the answer was 54% but the reason why she said that was that the person shaded in 46 meaning that what Shindi meant about the answer or the other reason was that the first answer (46%) was the real answer but it maybe was acutally 54% but anyway yeah.
In my opinion for this answer I just guessed but her is my solution:
On a graph it would show (sorry no pic :/) 100 so it would show as 10=1 as we keep going we get to 10 dividing it by 0.001 we would get 0.0001 so as we keep going 0.00001 we gotta reach 0.0000125 so here is my answer to that question:
0.1/ 10 = 0.01 / 10 = 0.001
then replace the one making it 125 so 0.125/ 10 = 0.0125
then 0.0125/ 10 = 0.00125 / 10 = 0.000125 / 10 = 0.0000125 and theres your answer
PLEASE COMMENT IF IM MISTAKEN ANYTHING!!!!!!!!
(sorry no pic I did this today and some questions i had no time to think)
Wednesday, January 13, 2010
First, I'll do question 4
Question no. 8
Question no. 9
* I'm not sure with my answer, that's why I looked at the back of the book, and the book mentioned that the answer is:
Question no. 16
Thanks for reading..
Please leave a comment..
Tuesday, January 12, 2010
In class we had to use 10x10 grids for solving percent problems.
For example if we had to shade in 65% of the grid we would shade 65 squares. Why? because percents are out of 100. We also had to show if we messed with a square so then we just make some sort of pop out to show what we did.
Well Harbeck tricked a lot of people when he said to fill in 3/4 of the grid a lot of people thought that 3/4 was 75% of the square so the shaded in 75% of the square but it actually meant that it only 3/4 or 75% of 1 square.
In class we also made a foldable.
In the foldable at the first flap we had to find the definition of percent and fractional percent. Under that we had to draw out what 180% , 0.6% and 12 3/4% looks like on a grid. We just have to draw it out and show a pop up where we messed with the square.
Percent- is a way of expressing a number as a fraction of 100.
Fractional Percent- a percent that includes a portion of a percent.
Thursday, January 7, 2010
3. Walter walks across a rectangular fi eld in a
diagonal line. Maria walks around two sides
of the fi eld. They meet at the opposite corner.
a) How far did Maria walk?
b) How far did Walter walk?
c2=104400 or 323m
c) Who walked farther? By how much?
Maria walked farther by 97 m
Find the height of the pole where the guy wire is attached to the nearest tenth of a metre.
Sorry there is no pic.
If the guy wire(c,10m) is the hypotenuse and the ground(a,2m) is one of the legs , then the pole(b) is the second leg.To do this we need the work.
square root of 96 =9.78 something,something,something,something
Round to the nearest meter to get 9.8m2
Again sorry about no pics I couldn't get onto my textbook (server lost) or something like that
Wednesday, January 6, 2010
a² = 80cm² - 79cm²
a² = (80x80) - (79x79)
a² = 6400cm - 6241cm
a² = 159cm
√a² = √159
7) What is the height of the wheelchair ramp? Give your answer to the nearest tenth of a centimeter.
(Sorry I didn't put the 'a,b,&c)
c² - b² = a²
80² - 79² = a²
Walter walks across a rectangular field in a diagonal line. Maria walks around two sides of the field. They meet at the opposite corner.
a) How far did Maria walk ?
I didn't really know how to find the length of what Maria walked so I added together the side lengths...
120 + 300 = 420
Maria walked 420m
b) How far did Walter walk ?
I used the Pythagorean relationship to find the answer...
a² + b² = c²
120² + 300² = c²
( 12o x 120) + ( 300 x 300) = c²
14400 + 90000 = c²
10 4400 = c²
√ 104400 = √ c²
323.1 = c
Walter walked 323.1m.
c) who walked farther ? by what distance ?
Maria walked farther by ... 96.9m
420 - 323.1 = 96.9m
~~~~~~~~~~~~~~~~~~~~~Question : Purple
Work : Blue
Answer : Bold
Me : Grey
Sorry if the picture is hard to read.
Thank you for reading my scribe...
please criticize and comment
What is the minimum distance the player
at third base has to throw the ball to get
the runner out at first base? Express your
answer to the nearest tenth of a metre
Okay, soo we need to find the hypotenuse
The shortest distance the 3rd basemen would have to thorw would be 38.18 meters.
14).the question for this is find the missing side length of each triangle.
a)c+b=d-each of these letters are supposed to be squared
12m+5m=d-each of these letters are supposed to be squared
(12mx12m)+(5mx5m)=d-the d is supposed to be squared
144+25=d-the d is supposed to be squared
169=d-the d is supposed to be squared
169=d-the d is supposed to be squared and their should be a square root over the 169 and d
b)w-t=v-each of these letters are supposed to be squared
15cm-9cm=v-each of these letters are supposed to be squared
(15cmx15cm)-(9cmx9cm)=v-the v is supposed to be squared
225-81=v-the v is supposed to be squared
144=v-the v is supposed to be squared
144=v-the v is supposed to be squared and their should be a square root over the 144 and v
So A's side length is 13m and B's side length is 12cm.
The question was: Find the height of the pole where the guy wire is attached to the nearest tenth or a metre.
So the height of the pole is 9.79.
Well hope my scribe post made sense. Please comment :D
Sarah has a vegetable garden in the shape of a right triangle. She wants to put fencing around it to keep the rabbits away.
a) What total length of fencing does she need? Give your answer to the nearest hundredth of a metre.
the square root of 7 is 2.6 which equals a2.
Sarah would need 9.6m of fencing.
b) If fencing costs $2/m, what would be the total cost of the fencing?
The fencing would cost $19.20, I got this answer by multiplying 9.6m by 2.
Tuesday, January 5, 2010
Here is question 15:
HOW LONG IS THE LINE?
To find the answer, we have to use the Pythagorean relationship. From looking at the graph we can tell that the legs, (green) have lengths of 2cm and 4cm. We have to find the length of the hypotenuse, (red). Our formula is: a squared + b squared = c squared.
By doing this we have figured out the area of the hypothetical square attached to the hypotenuse. Now we have to find the square root of that number to find the length of the hypotenuse.
the square root of 20= 4.4 (approx.)
The length of the line is approximately 4.4cm.
Thanks for reading! Please comment :)
And the right answer was 8.60 cm
For this question, I am supposed to find the length of the red line(C). I can do this by making a right triangle with the red line as the hypotenuse. The legs would meet each other at 5,2. The vertical leg (A) would be 4 units long and the horizontal leg (B) would be 2 units long. I can use this information to first, find out the length of C² and then find the length of C.
A² + B² = C²
4 cm² + 2 cm² = C²
(4 cm x 4 cm)+( 2cm x 2cm) = C²
16 cm + 4cm = C²
20 cm = C²
√ 20 cm = √ C²
4.5 cm= C
The red line has a length of 4.5 centimeters.