Question

Um jardim de forma retangular tem área de 54 m². Qual é o perímetro desse jardim, sabendo-se que a largura mede 3 m? 

56metros
62 metros
48 metros
42 metros
36 metros ​

Answer 1

$\large\boxed{\begin{array}{l}\underline{\rm \acute Area\,do\,ret\hat angulo}\\\underline{\rm de\,dimens\tilde oes\,c\,e\,\ell}\\\sf A=c\cdot\ell\\\underline{\rm Per\acute imetro\,do\,ret\hat angulo}\\\underline{\rm de\,dimens\tilde oes\,c\,e\,\ell}\\\sf P=2\cdot ( c+\ell)\\\sf c\longrightarrow comprimento\\\sf \ell\longrightarrow largura.\\\sf A=c\cdot\ell\\\tt dados:\begin{cases}\sf \ell=3\,m\\\sf A=54\,m^2\\\sf P=?\end{cases}\\\sf 54=c\cdot3\\\sf c=\dfrac{54}{3}\\\\\sf c=18\,m\end{array}}$

$\large\boxed{\begin{array}{l}\sf P=2\cdot(c+\ell)\\\sf P=2\cdot( 18+3)\\\sf P=2\cdot21\\\sf P=42\,m\end{array}}$