The area of a trapezoid is given by
[tex]A = \dfrac{(B+b)h}{2}[/tex]
where B and b are the minor and major bases, and h is the height.
The minor base is given, and it's 7 cm
The major base is the minor base plus the two pieces at the sides, so it's a total of 7+5+5=17.
The height is also given, and it's 5. So, the area is
[tex]A = \dfrac{(7+17)5}{2}=12[/tex]
