Respostas

2013-10-02T15:27:32-03:00
n=\frac{360}{\alpha} -1
20=\frac{360}{\alpha} -1
\frac{360}{\alpha}=20+1
\frac{360}{\alpha}=21 multiplicado cruzado temos:
21 \alpha=360
 \alpha=\frac{360}{21}=17,14^o
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