How do you solve for b in a + b + c = 180?

Jan 9, 2016

$b = 180 - a - c$

Explanation:

We want to isolate $b$ in $a + b + c = 180$.

Subtract $a$ from both sides.

$\textcolor{red}{a} + b + c + \textcolor{red}{- a} = 180 - a$

$b + c = 180 - a$

Now, subtract $c$ from both sides.

$b + \textcolor{red}{c - c} = 180 - a - c$

$b = 180 - a - c$