Cheatography

# Year 9 Mathematics Cheat Sheet by TryCryRepeat

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

### 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

 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

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)

### Formulae

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

### 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.

y = mx + c