ANSWER:
The area of the composite figure is 34 m^2
STEP-BY-STEP EXPLANATION:
To calculate the area of the complete figure, you have to separate the figure in two ways, just like this:
Figure A is a square and we calculate the area like this:
[tex]\begin{gathered} A_A=l^2 \\ A_A=4^2=16 \end{gathered}[/tex]Figure B is a trapezoid and we calculate the area like this:
[tex]\begin{gathered} A_B=\frac{b_1+b_2_{}}{2}\cdot h \\ A_B=\frac{4+8}{2}\cdot3 \\ A_B=18 \end{gathered}[/tex]Now the total area is the sum of both parts:
[tex]\begin{gathered} A_T=A_A+A_B \\ A_T=16+18 \\ A_T=34 \end{gathered}[/tex]