Sequence

$12 \quad \underrightarrow{{\color{#3D99F6}{+16}}} \quad 28 \quad \underrightarrow{{\color{#3D99F6}{+20}}} \quad 48 \quad \underrightarrow{{\color{#3D99F6}{+24}}} \quad 72 \quad \underrightarrow{{\color{#3D99F6}{+28}}} \quad {\color{#D61F06}{\boxed{100}}} \quad \underrightarrow{{\color{#3D99F6}{+32}}} \quad 132$

Since the second differences are 4, using the rule for quadratic sequences, you can see that $a_{n} = 2n^{2}+10n$ </br> From there, we can just plug in 5 for n and get 100 as an answer.