[Geometria]

por **Nookinho** » Ter Mar 04, 2014 21:54

Me ajudem nesta questão

por **DanielFerreira** » Qui Mar 06, 2014 22:29

Ângulo colaterais internos valem 180°:

$\\ \widehat{A} + \widehat{D} = 180^o \\\\ 120^o + \widehat{D} = 180^o \\\\ \boxed{\widehat{D} = 60^o}$

Lei dos Cossenos:

$\\ \overline{AC}^2 = (8)^2 + (12)^2 - 2 \times 8 \times 12 \times \cos 60^o \\\\ \overline{AC}^2 = 64 + 144 - 2 \times 8 \times 12 \times \frac{1}{2} \\\\ \overline{AC}^2 = 208 - 96 \\\\ \overline{AC}^2 = 112 \\\\ \overline{AC}^2 = \sqrt{16 \times 7} \\\\ \boxed{\boxed{\overline{AC} = 4\sqrt{7}}}$

[Geometria]

[Geometria]

[Geometria]

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