Revision Note

Interior Angle and Exterior of Polygon

Angle sum of polygon
Angle sum of $n$-gon $=(n-2)\times180

Math

Inverse Variation

If $y \propto \frac{1}{x}$ (i.e. $y$ varies inversely as $x… Read

Math

Joint Variation

If $y$ varies directly as $x$ and inversely as $z$, then we ha… Read

Math

Kites

Definition: A quadrilateral with two pairs of equal sides.

Math

Laws of Indices

For any real numbers $a$, $b$ and $c$, any rational numbers $… Read

Exponential and Logarithm

Laws of Logarithm

For any positive real numbers $a$, $b$ and $c$, any rational … Read

Exponential and Logarithm

Measurement of Sound

The relation between the loudness ($D$ dB) of a sound and the … Read

Exponential and Logarithm

Mid-point Formula

For two points $A(x_1,y_1)$ and $B(x_2,y_2)$, the coordin… Read

Coordinates

Mid-point Theorem

Condition: $AD=DB$ and $AE=EC$

Result: $DE//BC$ and $BC=2… Read

Math

Multiplicative Law

Let $E$ and $F$ be two events.

If $E$ and $F$ are independent e

Data Handling

Mutually Exclusive Events

Let $E$ and $F$ be two events. If $E$ and $F$ are mutually excl… Read

Data Handling

Normal Distribution

The mean, the median and the mode are the same.
The curve is be

Data Handling

Parallelograms

Definition: A quadrilateral with two pairs of parallel sid

Math

Partial Variation

If $y$ is the sum of two parts, one part varies inversely as $x… Read

Math

Percentage Changed

Percentage increase $=\dfrac{\mbox{New value}-\mbox{O

Math

Permutations

For $n$ different objects, if we select $r$ objects out of th… Read

Data Handling

Prism

Lateral surface area $=$ base perimeter $\times$ height
Vo

Math

Profit and Loss

Profit $=$ Selling price $-$ Cost
Profit percentage
$= \dfr

Math

Properties of Congruent Triangles

Corresponding sides
Condition: $\Delta ABC \cong \Delta X

Math

Properties of Parallel Lines

Corresponding angles

Result: $a=b$

Reference: corr. $\an

Lines and Angles