Question

a soma dos ângulos internos de um heptágono regular

Answer 1

180(n-2)
180(7-2)
180x5=900°

Answer 2

$\large\boxed{\begin{array}{l} \sf \:S_i = (n - 2) \: . \: 180 {}^{ \circ} \rightarrow \begin{cases} \sf \: S_i =somar\,dos\,\hat{a}ngulos\, internos\\\sf\:n = n\acute{u}mero\,de\, lados \end{cases} \\ \\ \sf \: S_i = (7 - 2) \: . \: 180 {}^{ \circ} \\ \\ \sf \: S_i = 5 \: . \: 180 {}^{ \circ} \\ \\ \boxed{ \boxed{ \sf{S_i = 900 {}^{ \circ} }}}\end{array}}$