Look at the picture.
We have two congruent trapezoids.
The formula of an area of trapezoid is:
[tex]A_T=\dfrac{b_1+b_2}{2}\cdot h[/tex]
[tex]b_1,\ b_2[/tex] - base
[tex]h[/tex] - height
[tex]b_1=11\\b_2=5\\h=3[/tex]
substitute:
[tex]A_T=\dfrac{11+5}{2}\cdot3=\dfrac{16}{2}\cdot3=8\cdot3=24\ units^2[/tex]
The area of the polygon is equal:
[tex]A=2A_T\to A=2\cdot24=48\ units^2[/tex]
Answer: b. 48 units²
