Question

EXERCÍCIOS

1) Calcule a área de um circulo cujo raio mede 4 cm.

2) Calcule a área de um circulo cujo raio mede 1,5 cm.

3) Calcule a área de um circulo cujo diametro mede 6 cm.

4) Calcule a área de um circulo cujo diámetro mede 7 cm

Answer 1

1) Calcule a área de um círculo cujo raio mede 4 cm:

$\Large\displaystyle\begin{gathered} \sf{ A=\pi\cdot r^2} \end{gathered}$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot4^2} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{A=3{,}14\cdot16 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \therefore\blue{\underline{\boxed{\boxed{\sf{A=50{,}24\,cm^2 }}}}} ~~(\checkmark).\end{gathered} }$

2) Calcule a área de um círculo cujo raio mede 1,5 cm:

$\Large\displaystyle\begin{gathered} \sf{ A=\pi\cdot r^2} \end{gathered}$

$\Large\displaystyle\text{ \begin{gathered} \sf{A=3{,}14\cdot1{,}5^2 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{A=3{,}14\cdot2{,}25 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \therefore\blue{\underline{\boxed{\boxed{\sf{ A=7{,}065\,cm^2}}}}}~~(\checkmark). \end{gathered} }$

3) Calcule a área de um círculo cujo diâmetro mede 6 cm:

$\Large\displaystyle\text{ \begin{gathered} \sf{A=\pi\cdot\bigg(\dfrac{d}{2}\bigg)^2 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot\bigg(\dfrac{6}{2}\bigg)^2} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot3^2} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot9} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \therefore\blue{\underline{\boxed{\boxed{\sf{A=28{,}26\,cm^2 }}}}} ~~(\checkmark).\end{gathered} }$

4) Calcule a área de um círculo cujo diâmetro mede 7 cm:

$\Large\displaystyle\text{ \begin{gathered} \sf{A=\pi\cdot\bigg(\dfrac{d}{2}\bigg)^2 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot\bigg(\dfrac{7}{2}\bigg)^2} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{A=3{,}14\cdot3{,}5^2 } \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \sf{ A=3{,}14\cdot12{,}25} \end{gathered} }$

$\Large\displaystyle\text{ \begin{gathered} \therefore\blue{\underline{\boxed{\boxed{\sf{A=38{,}465\,cm^2 } }}}}~~(\checkmark).\end{gathered} }$