Find out the missing term of the number series given below.

60, ?, 63.6, 70.8, 99.6, 243.6

The correct answer is 61.2.

To find the missing term in the given number series, let us denote the terms of the series as follows:

$T_1=60$
$T_2=?$
$T_3=63.6$
$T_4=70.8$
$T_5=99.6$
$T_6=243.6$

Let us calculate the differences between the consecutive known terms of the series:

$T_4-T_3=70.8-63.6=7.2$
$T_5-T_4=99.6-70.8=28.8$
$T_6-T_5=243.6-99.6=144.0$

Now, let us examine the pattern among these differences:

$28.8=7.2\times 4$
$144.0=28.8\times 5$

The differences are multiplied by consecutive integers ($\times 2$, $\times 3$, $\times 4$, $\times 5$) to get the next difference. Following this logic backward:

The difference between $T_3$ and $T_2$ should be:
$7.2÷3=2.4$

The difference between $T_2$ and $T_1$ should be:
$2.4÷2=1.2$

Using these values, we can determine the missing term $T_2$:

$T_2=T_1+1.2=60+1.2=61.2$

Let us verify this by calculating $T_3$ with our calculated value of $T_2$:

$T_3=T_2+2.4=61.2+2.4=63.6$

This matches the given third term of the series exactly. Therefore, the missing term is 61.2.