Find the series of this number $3,11,25,45$.

Step 1: Analyze the Pattern

The given numbers are $3,11,25,45$

Let us consider the missing term be $x$.

To find the value of $x$ let us understand the pattern between the numbers.

$11–3=8$

$25–11=14$

$45–25=20$

Step 2: Find the missing number

If we compare the numbers $8,14,20$ the difference between the numbers is six.

Every number result is raised by $6$.

So

$x–45=20+6$

$\Rightarrow x=45+26$

$=71$

Hence, the series is $3,11,25,45,71$.