Question

determine a soma dos angulos de um dodecagono

Answer 1

$\large\boxed{\begin{array}{l} \sf \:S_i = (n - 2) \: . \: 180 {}^{ \circ} \\ \\ \sf \:S_i = (12 - 2) \: . \: 180 {}^{ \circ} \\ \\ \sf \: S_i = 10 \: . \: 180 {}^{ \circ} \\ \\ \boxed{ \boxed{ \sf{S_i = 1800 {}^{ \circ} }}}\end{array}}$