The area of a rectangle is derived as follows;
[tex]\begin{gathered} \text{Area}=l\times w \\ l=5,w=4 \\ \text{Area}=5\times4 \\ \text{Area}=20cm^2 \end{gathered}[/tex]The perimeter is derived as follows;
[tex]\begin{gathered} \text{Perimeter}=2(l+w) \\ l=5,w=4 \\ P\text{erimeter}=2(5+4)_{} \\ \text{Perimeter}=2(9) \\ \text{Perimeter}=18\operatorname{cm} \end{gathered}[/tex]