Squaring numbers

Numbers could be squared using the following algorithm:

$\large {41 \times 41=\color{#3D99F6}40 \times \color{#D61F06}42 + \color{#69047E}1^2=\color{#20A900}1681 \\ 32 \times 32=\color{#3D99F6}30 \times \color{#D61F06}34 + \color{#69047E}2^2=\color{#20A900}1024 \\ 57 \times 57=\color{#3D99F6}54 \times \color{#D61F06}60 + \color{#69047E}3^2=\color{#20A900}3249 \\ 89 \times 89=\color{#3D99F6}88 \times \color{#D61F06}90 +\color{#69047E}1^2=\color{#20A900}7921 \\ \vdots }$

Find $78 \times 78$