How to calculate the area of a graph when $x$ and $y$ values are given? I have $x$ and $y$ values and I need to calculate the area of the graph with those $x$ and $y$ values. 

How can I calculate that? 

Please help me regarding this!
Say you have a function $f(x)$, and a set of domain values $\{a= x_0,x_1,x_2,\ldots,x_n=b\}$, where $x_{i+1}&gt;x_i$. The points $x_i$ partition the $x$-axis into a discrete set of subintervals $L_i = [x_i,x_{i+1}]$. You can approximate the area between the function and the $x$-axis for a given subinterval by the following formula (the trapezoid rule):

$$ A_i =  |L_i|\times \frac{f(x_i)+f(x_{i+1})}{2},$$

where $|L_i|=x_{i+1}-x_i$ is the length of the subinterval. The total  approximated area between $a$ and $b$ is just the sum of all the areas,

$$A=\displaystyle\sum_{i=0}^{n-1} A_i.$$

You can find an interactive demo of the trapezoid rule here. Loosely speaking, the greater the value of $n$ the better the approximation of the area.
This is the formula you are looking for I suppose:

$$\text{Area}=\int_{a}^{b}{f(x)\:dx},$$

Where $a$ and $b$ are your limits of integration and $f(x)$ is the function of the graph.