[tex]P_1 = 2 m\times 4 m= 8 {m}^{2} [/tex]
[tex]P_2 = 1m \times 4m = 4 {m}^{2} [/tex]
[tex]P_c = 8 {m}^{2} + 4 {m}^{2} = \boxed{ 12 {m}^{2} }[/tex]
