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

60, ?, 63.6, 70.8, 99.6, 243.6

To find the missing term of the number series, let us analyze the pattern of differences between consecutive terms.

Let the given series be:
$T_1=60$
$T_2=?$
$T_3=63.6$
$T_4=70.8$
$T_5=99.6$
$T_6=243.6$

First, let's calculate the differences between the known consecutive terms at the end of the series:

$T_6-T_5=243.6-99.6=144$

$T_5-T_4=99.6-70.8=28.8$

$T_4-T_3=70.8-63.6=7.2$

Now, let us examine the relationship between these differences: 7.2, 28.8, and 144.

We can see that:
$28.8/7.2=4$
$144/28.8=5$

The ratio of the differences is increasing by 1 each time. Specifically:
The difference between the 3rd and 4th term is $d_3=7.2$.
The difference between the 4th and 5th term is $d_4=7.2\times 4=28.8$.
The difference between the 5th and 6th term is $d_5=28.8\times 5=144$.

Following this pattern backwards:
The difference between the 2nd and 3rd term ($d_2$) multiplied by 3 should equal the next difference 7.2.
$d_2\times 3=7.2\Rightarrow d_2=2.4$

Similarly, the difference between the 1st and 2nd term ($d_1$) multiplied by 2 should equal the next difference 2.4.
$d_1\times 2=2.4\Rightarrow d_1=1.2$

Let us verify this by calculating the missing term $T_2$:
Using $d_1=1.2$:
$T_2=T_1+1.2=60+1.2=61.2$

Let us check if this matches with $T_3$:
$T_3=T_2+2.4=61.2+2.4=63.6$, which is indeed the third term in the series.

Therefore, the missing term is 61.2.