Mathematical Formulas - Secondary 1 & 2

Concept sheet | Mathematics

Arithmetic and Algebra

Expressing a Number as a Percentage

​||\dfrac{\text{numerator}}{\text{denominator}}\times100||||\dfrac{\text{numerator}}{\text{denominator}}=\dfrac{\text{number sought}}{100}||

The Properties of Operations

PropertyAdditionMultiplication
  1. Commutativity
||a+b=b+a||||a\times b=b\times a||
  1. Associativity
||(a+b)+c=a+(b+c)||||(a\times b)\times c=a\times(b\times c)||
  1. The neutral (identity) element
||a+0=0+a=a||||a\times1=1\times a=a||
  1. The absorbing (annihilating) element
 ||a\times0=0\times a=0||
  1. Opposite / Reciprocal
||a+-a=-a+a=0||||a\times\dfrac{1}{a}=1||
  1. The distributive nature of multiplication
||a\times(b\pm c)=a\times b\pm a\times c||

Geometry

Converting Units of Measure

​|\text{km}|​|\text{hm}|​|\text{dam}|​|\text{m}|​|\text{dm}||\text{cm}|​​|\text{mm}|
In this direction |\Rightarrow \times 10\qquad \qquad\qquad| In this direction |\Leftarrow \div 10|
​|\text{km}^2|​|\text{hm}^2|​|\text{dam}^2||\text{m}^2|​​|\text{dm}^2|​|\text{cm}^2|​|\text{mm}^2|
In this direction |\Rightarrow \times 100\qquad \qquad\qquad| In this direction |\Leftarrow \div 100|
​|\text{km}^3|​|\text{hm}^3|​|\text{dam}^3|​|\text{m}^3|​|\text{dm}^3|​|\text{cm}^3|​|\text{mm}^3|
In this direction |\Rightarrow \times 1000\qquad \qquad\qquad| In this direction |\Leftarrow \div 1000|

The Perimeter and Area of Plane Figures

FigurePerimeterArea
TriangleThe sum of all sides

|A =\dfrac{b\times h}{2}|

|A = \sqrt{p(p-a)(p-b)(p-c)}|
where
|p=\dfrac{a+b+c}{2}=| half-perimeter

|A=\dfrac{ab\sin C}{2}|
where |C=| measure of the angle located between sides |a| and |b|

Square|P=4 \times s||\begin{align} A &= s \times s\\
A &= s^2
\end{align}|
Rectangle|\begin{align} P &= b+h+b+h\\
P &= 2(b+h)
\end{align}|
|A=bh|
RhombusP=|4 \times s||A=\dfrac{D\times d}{2}|
ParallelogramThe sum of all sides|A=bh|
TrapezoidThe sum of all sides|A=\dfrac{(B+b)\times h}{2}|
Regular polygon|P=n \times s||A=\dfrac{san}{2}|
Any polygonThe sum of all sidesThe sum of the areas of all the triangles that make up the polygon
Circle|\begin{align} d &= 2r\\\\
r &= \frac{d}{2}
\end{align}|
||\begin{align} C &= \pi d\\\\
C &= 2 \pi r
\end{align}||
|A=\pi r^2|
Circular arc and sector of a circle|\displaystyle \frac{\text{Central angle}}{360^o}=\frac{\text{Arc length}}{2\pi r}||\displaystyle \frac{\text{Central angle}}{360^o}=\frac{\text{Area of sector}}{\pi r^2}|

Measurements in Polygons

Total number of diagonalsNumber of diagonals at each vertexSum of the measures of the interior anglesMeasure of an interior angle
|\dfrac{n(n-3)}{2}||n-3||180(n-2)||\dfrac{180(n-2)}{n}|

The Area of Solids

​SolidsLateral areaTotal area
​Prism and cylinder

Sum of the areas of the lateral faces of the solid

|A_L=P_b\times h|

​Sum of the areas of all faces of the solid

|A_T = A_L+2A_b|

​Pyramid and cone

​Sum of the areas of the lateral faces of the solid

|A_L=\displaystyle \frac{P_b\times a}{2}|

Sum of the areas of all faces of the solid

|A_T = A_L+A_b|

​Sphere|A=4\pi r^2|

Similar Figures

Similarity ratio (Scale factor)Area ratio
||k=\dfrac{\text{Length of image figure}}{\text{Length of initial figure}}||||k^2=\dfrac{\text{Area of image figure}}{\text{Area of initial figure}}||

Probability and Statistics

The Probability of Events

ConceptFormulas
​Probability||\text{Probability}=\dfrac{\text{No. of favourable outcomes}}{\text{No. of possible outcomes}}||
​​Complementary probability||\mathbb{P}(A')=1-P(A)||
Probability of incompatible events||\mathbb{P}(A\cup B)=\mathbb{P}(A)+\mathbb{P}(B)||
​Probability of compatible events||\mathbb{P}(A\cup B)=\mathbb{P}(A)+\mathbb{P}(B)-\mathbb{P}(A\cap B)||