Showing posts with label Grade 8 Maths. Show all posts
Showing posts with label Grade 8 Maths. Show all posts

Wednesday, 19 March 2014

Probabilty

Probability means how likely it is that something will happen. For example getting two sixes when you roll a pair of dice (dice is the plural of 'die').


Relative frequency

How often something happens divided by all outcomes.

Circles and Prisms

Circumference of a Circle:

Circumference means the perimeter of a circle


Circumference = 2 × π × Radius

Area = π r2

Prisms

A prism is an object that has the same area all along its length.
 
We can find the volume of a prism by multiplying the area of the base by the length.



Bearings and loci

Objectives 

  • Bearings

  • Locus from a fixed point

  • Constructing a perpendicular bisector

  • (to find the locus that is equidistant from two points)

  • Locus from a line

  • Constructing the bisector of an angle

  • (to find the locus that is equidistant from two lines)


Bearings


Locus from a fixed point

A locus means a path. 'Loci' is the plural of locus. It shows us the path or region that a point can travel according to certain rules. 

The locus of all points at a fixed distance from a line.Watch the video here.



The locus of points that are equidistant from two points: Constructing a Perpendicular Bisector

You can find the method by clicking on the image below:
Watch the video.




The locus of all points that are equidistant from two lines: Bisecting an angle



We use this method to find the locus of all points that are equidistant from two lines.

Some real world examples of loci

Watch a video of how loci apply in the real world.


Tuesday, 18 March 2014

Graphing and Solving Linear Equations

  • The equation of a line
  • Solving two simultaneous equations using a graph
  • Trial and Improvement method to solve an equation

Linear Equations



Solving two simultaneous equations using a graph




Trial and Improvement method to solve an equation

Using this method we 'guess' the first value x and then try other values until we find one that works. Click the image below for an example:




Monday, 10 March 2014

Reflection, Translation, Rotation and Enlargements

Reflection:




Translations






Rotation






Enlargement


Click the image above for more information, watch a video here.

Enlargements






Tuesday, 4 February 2014

Constructions

- Constructing the perpendicular bisector of a line
- Finding the perpendicular from a point to a line
- Bisecting an angle


Constructing a Perpendicular Bisector

You can find the method by clicking on the image below:
Watch the video.




Bisecting an angle

Sunday, 2 February 2014

Angles of Polygons


Interior and Exterior Angles





Exterior Angles of a Polygon
Remember, a polygon is any shape that has 3 or more straight sides (no curves).

Click on the hexagon above to see that:

The exterior angles of any polygon add up to 360°

Interior Angles

90° + 60° + 30° = 180°

80° + 70° + 30° = 180°

It works for this triangle!

Let's tilt a line by 10° ...
It still works, because one angle went up by 10°, but the other went down by 10°
The Interior Angles of a Triangle add up to 180° 






Because there are Two Triangles in a Square
The interior angles in this triangle add up to 180°

(90°+45°+45°=180°)
... and for this square they add up to 360°
... because the square can be made from two triangles!






Because a pentagon has three triangles, the sum of the interior angles add up to 3x180° = 540°






 In general:

The sum of the interior angles of a polygon that has n sides, is:

(n-2) x 180°

Triangles in a circle:

The triangle drawn on the diameter of a circle is always 
a right angled triangle





Monday, 13 January 2014

Areas and volumes

Objectives:

  • Area of rectangles and triangles

  • Area of parallelograms and trapeziums

  • Volume of cuboids

  • Parts of a circle, circumference and area.

 

Area of a rectangle:



Area of a triangle:

More: Area of a triangle inside a rectangle

Area of a parallelogram:



Area of a trapezium:

(Note: this shape is also known as a trapezoid, but for your exam just use trapezium!)


Cuboids

A cuboid is a box-shaped object. Click the image below for more information.

V = l × w × h

Nets

A 'net' is the shape you get when you cut along the edges of a three dimensional object and lay it out flat.

 

Parts of a circle:






Copy the picture below, label the green and blue sections:
Answer is here.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Circle: Area and circumference


Homework:

P162  Ex 18.1     Q 3

P165  Ex 18.2A  Q3

P165  Ex 18.2B  Q 1b, Q2b

P170  Ex 18.3B  Q 1, 2

P172  Ex 18.4     Q 3

P174  Ex 18.5A   Q 1 - 9

P176  Ex 18.5B  Q 1c, 1d, 2c, 2d.

P177  Ex 18.5C  d, e






Tuesday, 7 January 2014

Angle Properties

  • Identify: Supplementary, vertically opposite, corresponding and alternate angles.

  • Know that angles of a triangle add up to 180°

  • Know that the exterior angle of triangle is equal to the sum of the two interior opposite angles.

  • Know that angles of a quadrilateral add up to 360°


Supplementary Angles (add to 180°)

 

Vertically Opposite Angles..... are equal

Corresponding Angles (look for an 'F' shape)...... are equal

 


Alternate Angles (look for a 'Z' shape)....are equal




Angles of a triangle add up to 180°


A + B + C = 180°


Exterior angle of triangle is equal to the sum of the two interior opposite angles.

C = A + B


Angles of a quadrilateral add up to 360°


80° + 100° + 90° + 90° = 360°



Homework:

P153  Ex 16.4C  Q3-6 

P156  Ex 17.1B  Q4-8

P158  Ex 17.2     Q3, 5, 6

P160  Ex 17.3A  Q3, 4

P160  Ex 17.3B   Q1, 4




Tuesday, 17 December 2013

Form 8 Christmas Revision

Please download the Christmas revision document available at the following link:

http://sdrv.ms/1c8Sc7r




 
Please review the work we have done this year and on here.
Have a great Christmas and New Year!
Best wishes,
Mr. Healy





Tuesday, 19 November 2013

Fractions, Decimal and Percentages

Objectives:

  • Convert fractions to decimals

  • Change decimals to fractions

  • Putting fractions in order -converting to decimals -common denominators

  • Calculating a fraction of a quantity

  • Mixed numbers

  • Multiplying and dividing by fractions

  • Percentages


Fractions Review

Decimals



Percentages




Homework

Exercise 15.1A Fractions to Decimals

Q3

Q6




Exercise 15.1B Decimals to fractions

Q3, 4




Exercise 15.1 C Ordering
Q 1, 2 Q 3, 4




Exercise 15.2A Mixed Numbers

Q 4, 5, 6




Exercise 15.2B + & -

Q 4, 6




Exercise 15.2C x & ÷

Q 3, 4
Q 9, 10

Exercise 15.3A
Percentages


Q 3, 4




Exercise 15.3 B



Q 3, 4

Q 9, 10

Monday, 11 November 2013

Statistical Calculations

Objectives:

  • Calculating the mean, median, mode and range for statistical data.

  • Know which is the best to use.



Review of mean, median and mode:














Large and small values

You need to know that very large or very small figures in a list of data can affect the mean and the range.
The median and the mode are less affected.

Homework:

Page 112  Ex. 12.1   Q:1

Page 115  Ex  12,2   Q:2





 

Saturday, 2 November 2013

Letters as numbers and solving equations

Objectives:

  • Link numbers to letters. 

  • Solve equations: know that what we do on one side of the equation we must do on the other.

  • Write mathematical sentences.



Linking numbers to letters.






Try the quiz:

Monday, 28 October 2013

Order of operations, Indices

Order of Operations:


 

Order of operations with numbers and letters:


What is the meaning of "Like and unlike terms"?

Solving Equations: