"Area of a Triangle"

Triangle

Triangle:
A three sided figure
Have three angles

e.g.

Because triangle is half of a square, rectangle, or a parallelogram, the formula for finding the area of triangle is Base x Height divided by two.





or area= 45 meters squared




Here is some link to truelly understand how to finding the area of a triangle:

http://www.youtube.com/watch?v=xz6gBA0M9FY&feature=related

Area

Areas - the number of square units contained in a two dimensional shape


this square has an area of 4 square units









Area is the surface space a shape takes up.

Area of square or rectangle
Length x Width= area
L x W= area

eg.
area=L x W
area= 6x3
=18cm2




Parallelogram - a four sided figure with opposite sides parallel and equal



eg.










Base(b) - a side of two-dimensional closed figure(shape)








Height(h) - the perpendicular distance from the base to the opposite side.








Base(b) is 5cm and height(h) is 3cm. Plug those value into the formula

A=b x h
A=5 x 3
A=15cm2


Find the area of this parallelogram






Find the area of this parallelogram

A=b x h
A=12 x 4
A=48m squared




Homework:

Angles

Angles - space between 2 connecting lines

Acute - an angle that is less than 90°

Obtuse- an angle that is greater than 90°and less than 180°

right- exact 90°

straight- 180°

angle bisector-the line that divides an angle into 2 equal parts

-equal angles are not mark with the same symbol

How to make an angle bisector

Method 1

1. use compass make an arc from the vertex that crosses both arms label them X and Y.

2. make an arc from point X and Y they must be equal size.

3. draw a line from point B to the arc intersection.

Method 2

1. use protractor measure the angle D,E,F .

2. divide your measurement by two.

3. make at 54 using protactor labelled Q

y) Join point Q with a straight line.

How to make Perpendicular lines.

Bisect
Bi- means two
Sect- means to cut
So bisect means to cut in two.

Directions:
1. Draw a line
2. Fold so pt A is on top of pt B.
3. Use a ruler to draw a line in the crease made by the fold.
4. Label the point where the two lines segments intersect P.
5. Measure the lengths of AP and BP
What do you noticed?
7. Use a protractor to measure the 4 angles created.
What do you notice? they are all 90*

You have created a perpendicular bisector
- a line that divides another line segment in half and is at right angles to it.
-equal line segments are marked with " hash" marks.



use a right triangle
1. Find the length of the line segment.
2. Determine the half way point.
3. Use right triangle to create a perpendicular line.


3rd way to make a perpendicular bisector.
use compass.



step one: make an arc from point A is greater then half way.
step two: make an equal sized arc intersections with a straight line, that line is a perpendicular bisector.


Draw a 12cm line segment label it PQ. Draw the perpendicular bisector of this line segment, all three was. Label the point where they intersect R.
a. what are the lengths of PR and PR?
b. what does it mean if the lengths are different?

Geometry

Parallel-describes lines in the same plane that never cross or intersect.

-they are marked using arrows.

Perpendicular-describes lines that intersect at right angles (90 degrees).

-they are marked using a small square.

Measure the distance from:

A to B = 8.9 cm

B to C = 8.9 cm

E to F = 8.9 cm

F to G = 8.9 cm

I to J = 8.9 cm

J to K = 8.9 cm

What do you notice about parallel lines?

Always are the same distance apart no matter where you measure as long as you measure using parallel lines.

Identify any parallel line segments

AE // BF

BF // CG

EI // FJ

FJ // GK

AI // CK

Identify any perpendicular line segment

AE to DF

BF to EG

CG to FH

IE to DF

HOMEWORK!!

1. Are line segments AC and DF parallel?

2. Are line segments DF and BE perpendicular?

3. Are line segments AC and BE perpendicular? How do you know?

4. Would a line segment joining A to D be parallel to a line segment BE? How do you know?

Term Test

A reminder that we have a quiz on Tuesday, covering adding, subtracting, multiplying, and dividing decimals. Order of operations will be covered on the test as well.

Lastly, we have a Term Test on Thursday it will cover the entire term's worth of work. Be sure to start studying now, do not wait until the last minute!

Number of the Day

Today's Number is : 8497.365.

Half of the number of the day is: 4248.6825.

Write the number of the day in expanded form: 8000+400+90+7+0.3+0.06+0.005=8497.365.

Write the number of the day in written form: eight thousand four hundred ninty-seven and three
hundred sixty-five thousandths.

Round the number of the day to 100: 8500.

What digit is in the tenths place: 3.

The number of the day doubled is:16994.730.

123.45 more than the number is: 8620.815.

987.65 less then the number is: 7509.715.

Cube the digit in the ones place: 7 times 7 times 7 = 343.

Square the digit in the hundreds place: 4 times 4 = 16.

Divide the number by 3.55 and round to the nearest hundredth: 2393.62.

The product of all the digits in the number of the day is: 8 times 4 times 9 times 7 times 0.3 times 0.06 times 0.005= .181440.



Homework

p.g 71-73 # 4 - 24 even only.





DON"T FORGET!!!!

QUIZ ON TUESDAY AND TEST ON THURSDAY

so study, study, sudy!!!!!!!!

Number of the Day Answers :)

Today's number: 2691.348

1. 1345.674

2.2000+600+90+1+0.3+0.04+0.008

3.two thousand six hundred ninety one and three hundred forty eight thousandths

4.2700

5.3

6.5382.696

7.2814.798

8.1703.698

10.1

11.36

12.758.13

13.10,368


If you have any problems, just ask!

LEAVE A COMMENT :)

Scribe Post November 3, 2009

What we did today;
We had to use BEDMAS to explain these equations
BEDMAS means :
Brackets
Exponents
Division
Multiplication
Addition
Subtraction

A)
2+3x4=
2+12
= 14

B)
10-6/2=

10-3

=7

C)
(2+3)x4=
5x4
=20

D)
(10-6)/2=
4/2
=2

E)
8/2²=
8/4
=2

F)
4x3/2+5=
12/2+5
6+5
= 11

G) Create a math equation including +,-,/,x, exponents, and brackets. The answer must be 6 and you can't repeat any digits or use zero.

(8/4) x1²+9-5
2x1+9-5
2+9-5
11-5
= 6

Here is a video to help you with BEDMAS and a link to help you understand BEDMAS:

BEDMAS

Order of operations

There are four operations

-Multiplication,Division=brothers
-Addition,subtraction=sisters

1st: brackets
2nd:exponents
3rd:division or multiply in order form left to right
4th: addition or subtraction in order form left to right


6.4+120x1.25=158


2x3/6+(2-1)=2

Annie has been asked to calculate.1.7+6+2=. She claims the answer is 3.85. Do you agree?Explain why or why not.