Answer
$\color{red}{x=57}$
Work Step by Step
$$\text{Solution}$$
Given Information:
Data Set ⟹ $(30, 45, \color{red}x, 100) $
Total Number of Items in Data Set $n= 4$
Median =$51 $
To Find: Value of $\color{red}x$
Median for even Numbers $ =\frac {(\frac{n}{2})^{th}+ (\frac{n}{2})^{th}+1}{2}term$
Median for even Numbers $ =\frac {(\frac{4}{2})^{th}+ (\frac{4}{2})^{th}+1}{2}term$
Median$=\frac {(2)^{nd}+ (3)^{rd}}{2}term$
Median = $51$
$2^{nd}$ term =$45$
$3^{rd}$ term $=\color{red}x$
$51 = \frac {45+\color{red}x}{2} $
$45+\color{red}x=51\times2$
$\color{red}x=102-45$
$\color{red}x=57$
