[tex]\Large\boxed{\begin{array}{l}\underline{\rm Observe~a~figura~que~eu~anexei}\\\tt a )~\sf tg(30^\circ)=\dfrac{4\sqrt{3}}{x}\\\\\sf\dfrac{\backslash\!\!\!\!\sqrt{3}}{3}=\dfrac{4\backslash\!\!\!\!\sqrt{3}}{x}\\\\\sf x=3\cdot4\\\sf x=12~cm\\\sf A=b\cdot h\\\sf A=12\cdot4\sqrt{3}\\\sf A=48\sqrt{3}\,cm^2\end{array}}[/tex]
[tex]\Large\boxed{\begin{array}{l}\tt b)~\sf h=5\sqrt{3}\\\sf tg(60^\circ)=\dfrac{h}{a}\\\sf \backslash\!\!\!\!\sqrt{3}=\dfrac{5\backslash\!\!\!\!\sqrt{3}}{a}\\\\\sf a=5\\\sf B=2a+3=2\cdot5+3=13~cm\\\sf b=3~cm\\\sf A=\dfrac{(B+b)\cdot h}{2}\\\\\sf A=\dfrac{(13+3)\cdot5\sqrt{3}}{2}\\\\\sf A=\dfrac{16\sqrt{3}}{2}\\\\\sf A=8\sqrt{3}\,cm^2\end{array}}[/tex]
