Glenesse's Math Question

My question is # 28 in chapter 2.4.

Question:

The period, t, in seconds, of a pendulum is the time for a complete swing back and forth. The period can be calculated from the length, l, in metres, of the pendulum using the formula t = √4l. Determine the period of a pendulum with each of the following lengths. Express each answer to the nearest hundredth of a second.

a) 1.6 m

b) 2.5 m
c) 50 cm

Answers:

a) The period of a pendulum with the length of 1.6 m is 2.53 (s) seconds.

I first multiplied the length, which was 1.6, by 4 and got 6.4. I then square rooted that and got 2.53 s.

b) The period of a pendulum with the length of 2.5 m is 3.16 (s) seconds.

I first multiplied the length, which is 2.5, by 4 and got 10. I then square rooted that and got 3.16 s.

c) The period of a pendulum with the length of 50 cm is 1.41 (s) seconds.

I first multiplied the length, which is 50, by 4 and got 200. I then square rooted that and got 14.14, but I had to divide that by ten because we need to get from cm to m. I then got 1.41 s.

Marilen's 2.4 #34 Question

-- What I Did --

Step 1.
First, I plugged in the numbers in the equation. A = 40m2.


Step 2.
I then solved the equation inside of the square root. So I did 40m2/π.

Rounded to the nearest hundreth place, 40/π = 12.73

Step 3.

You must now solve the equation of the square root of 12.73.

So, R= 3.6m, rounded to the nearest tenth.

A link to squares and square roots

A video to square roots:

Paul's 2.4 #31 question.

First of all we have to find the s which is a + b + c / 2














Now that you found the s ,you can now do the formula to find the area of the triangle














Just continue the formula. a, b, and c represent the side lengths of the triangle. Just repeat this formulas for the nest question.

B)




























Here's a video about square root:

Finding sqaure roots of rational numbers

√25
When we find a square roots we are finding the number that represents one side of a square. Why only one side? Because the length of one side is the same as all other sides and a square has 4 equal sides.

Then √25 is 5

√16/49
The square root is 4/7 because 4/7 x 4/7 = 16/49

√25/81 =5/9

√0.0144= 0.12
Check your answer: 0.12 x 0.12= 0.0144
In the question 0.12 x 0.12 there are 4 decimal places in the question and 4 decimal places in the answer.

√0.0081= 0.09
Check your answer: 0.09 x 0.09 =0.0081

√0.00025= 2.846049894
This is not a perfect square.

*You will need an even amount of decimal places for a perfect square *

√8.1= 2.846049894
This is not a perfect square because there is only 1 decimal place.

√8.10 is the save as √8.1
The reason for this is because the zeros after the last significant digit after the decimals does not change it's value.

3√64= 4
4 is the side length of a cube.
Cube = 4x4x4= 64

HOMEWORK!!
- Page 78 # 2 and 4
- Practice: 5 or 6, 7 or 8, 9 or 10, 11 or 12, 13 or 14
- Apply: All even or all odd and # 31
- Extend: Any 3
- Homework Book: 2.4, all of extra practice.
- Blog Post and comment on at least 4 blogs. If there are already 4 comments do NOT comment on that blog.

Mangahigh: FAI-TO
Tonight, November 14, 2011 we will be joining a fai-to at 7PM. Please go against Porchester school.

Chapter 2.3: Question #16

Question:

Boris has 2 1/2 times as much cash as Anna. Charlie has 3/4 as much cash 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?

Answers:

a) The three people have $108.80 all together.

1) First I multiplied 2 1/2 by 25.6o.

2) Second I multiplied 3/4 by 25.60

3)Then for question a) I added how much Boris had, which was $64, then added how much Charlie had, which was $19.20, then lastly I added how much Anna had, which was $25.60.

b) Boris has $44.80 more than Charlie.

1) I used the answers i got from question a) for question b).

2) I subtracted what Charlie had, which was $19.20, from what Boris had, which was $64.

CHAPTER 2.2; #22

PS: Just enlarge the pictures by clicking on it if you cannot read it =)

Math Textbook: 2.2 #26

26. Four points, A, B, C, and D, have the following co-ordinates:
A(0.75, 0.81)
B(0.75, -0.65)
C(-1.22, -0.65)
D(-1.22, 0.81)

What is the area of quadrilateral ABCD, to the nearest hundreth of a square unit?

--- What I did ---

Step 1: In my head, I imagined and took a guess on where the co-ordinates would show up on a co-ordinate grid.

Step 2: I then had to determine the length between A and B, using the x-axis co-ordinates. The co-ordinates for A and B are 0.81 and (-0.65). To find the difference between those 2 numbers, you would need to subtract.

The difference between 0.81 and (-0.65) is 1.46. So, the length between x-axis co-ordinates A and B is 1.46 units.

Step 3: I then had to find the length between A and D, using the y-axis co-ordinates. The co-ordinates for A and D are 0.75 and (-1.22). To find the difference between those 2 numbers, you would need to subtract.

The difference between 0.75 and (-1.22) is 1.97. So, the length between x-axis co-ordinates A and D is 1.97 units.

Step 4: You need to find the area of ABCD. To find the area of quadrilateral ABCD to the nearest hundreth of a square unit, you use the formula length x width.

The area of quadrilateral ABCD to the nearest hundreth of a square unit is 2.88u2.

Math Textbook: 2.2 #17- Mark Castillo

What I first did for this question was add 1.35m and 0.83m:

1.35 + 0.83= 2.18m

Next it says that there is an end overlapping and is 12cm long.

I made 12cm into 0.12m because there is 100cm in 1m and in decimal form it would be 1.00m.

Then all you have to do next is subtract 2.18m and 0.12m

2.18 - 0.12= 2.06

The total length of the new pole in meters is 2.06m.

Math Textbook 2.3 #18

In the instruction it said that one ninth of the height of an iceberg is above water. I assumed that the ice underwater is eight ninth or the rest of the height.








If I divide the eight ninth underwater by eight it will give me one ninth. The height of the iceberg above surface in the nearest tenth is 9.5 metres.

Dividing Rational Number in Fraction Form

Step 1
-Change Mixed fractions to improper fractions
Step 2
-Make the problem simpler by dividing by 1
-Multiply the divisor by its reciprocal and the dividend by the same reciprocal
Step 3
-Simplify if possible






















































Here is a link to :
Dividing Rational Number in Fraction Form



Homework:
-Journal
-Finish 2.3 and Yellow decimal sheets
-Start Fraction yellow sheet

Comparing and Ordering Rational Numbers

Quiz

Change 0.13repeating into a fraction: 2/15

What is between 1/5 and 2/3? 0.

What is -0.4 as a fraction (in lowest terms): -2/5

*If there is a odd number of negative signs, the answer is a negative*

*If there are a even amount of negative signs, the answer is positive*

HOMEWORK:

Check Your Understanding #1-3 pg. 51-54

Practise: 4 or 5, 6 or 7, 8 or 9, 10 or 11, 11 or 12, 12 or 13, 14 or 15, 16 or 17

Apply Odd or Even

Extend 28, 29, 30

ALSO! DON'T FORGET TO BE STARTED ON YOUR BIRDHOUSE, IT IS DUE ON MONDAY!

MELANIE ILAGAN IS DOING THE NEXT BLOG POST.