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Year 9 Mathematics Cheat Sheet (DRAFT) by

I’m just trying to pass with a high grade in my exams.

This is a draft cheat sheet. It is a work in progress and is not finished yet.

REMEMBER TO ROUND THE DECIMA­LS!!!

E.g. 1.27969 would round to 1.28

Similarity and Congruence

Terms
Congruent Shapes
Similar shapes that have been moved in some way
Rotation
The shape has been turned over
Reflection
The shape has been flipped over as if it was reflected in a mirror
Transl­ation
The shape keeps its same orient­ation, but it has been simply moved

Radicals and Pythagoras

Pythagoras Theorem:
a2 + b2 = c2

Statistics

Types of Data
Catego­rical
A collection of inform­ation that is divided into groups.
Numerical
Data in the form of numbers.
Terms
Range
Biggest number - smallest number
Terms
Sum of all values divided by the number of values.
Median
The middle number of a numerical data set. If there are 2 medians use this formula: (a+b) / 2
Mean
Sum of all values divided by the number of values.
Mode
The number with the highest frequency (most occurr­ing).
/ = divide

Probab­ility

 
 

Similarity and Congruence

A’B’ / AB
B’C’ / BC

Coordinate Geometry

Distance Formula:
d = (x2 - x1)2 + (y2 - y1)2
Midpoint Formula:
(x1 + x2 / 2 , y1 + y2 / 2)
Gradient Formula:
y2 - y1 / x2 - x1
/ = fraction (divide)

Graphing Lines From Equations

y = mx + c
 

Formulae

a = 10, b = 5, c = 15
Find d if d = ab + c
d = 10 x 5 + 15 = 65

Formulae

Trigon­ometry

 
Sine O/H
θ = Delta
Cosine A/H
 
Tangent O/A
When finding θ (Delta) you use Sin-1, Cos-1 and Tan-1. When you type it into the calculator press shift.

Measur­ement