##### Indices and Surds

### Laws of Indices

a^{m} x a^{n} = a^{(m+n)}

a^{m} / a^{n} = a^{(m-n)}

(a^{m})^{n} = a^{(mn)}

a^{(-m)} = 1/(a^{m})

a^{0} = 1

a^{1} = a

##### Quadrilateral

A quadrilateral is a polygon with four sides (edges) and four vertices (corners). The word quadrilateral is made of the words quad (meaning four) and lateral (meaning sides). So, quadrilateral is simply a four sided figure.

##### Similar Triangles

Two figures are said to be similar, if they have the same shape but not necessarily the same size. If the angles of one triangle are equal to the angles of another triangle, then the triangles are said to be **Equiangular**. Equiangular triangles have the same shape but may have different sizes. Therefore, equiangular triangles are also called **Similar Triangles**.

##### Number Systems #2

Representing a number as prime factors helps in analysing problems.

##### Logarithms

Logarithm is the **exponent or power** to which a stated number called the base is raised to yield a specific number. For example, in the expression 10^{2} = 100, the logarithm of 100 to the base 10 is 2.

##### Simple Interest

The lending and borrowing of money involves the concept of simple interest and compound interest. If you borrow money for certain period of time, you have to return the borrowed sum of money (**Principal**) with some extra money. This extra money is called **Interest**.

##### Mensuration

**Mensuration** is the branch of Mathematics which deals with the study of geometric shapes, their **area**, **volume** and different parameters in geometric objects.

##### Geometry Basics

Geometry is branch of mathematics concerned with shapes, sizes and properties of figures. Geometry includes knowledge of angles, lines, triangles, quadrilaterals, circles and polygons.