Answer: 18
Step-by-step explanation:
Here you have two triangles and a square. Or what's also called a trapezoid.
[tex]A=\frac{a+b}{2}h[/tex]
a = shorter side = 3
b = longer side = 9
h = height = 3
[tex]A=\frac{3+9}{2}(3)[/tex]
[tex]A=\frac{12}{2}(3)[/tex]
[tex]A=6*3\\A=18[/tex]
