We have two congruent trapezoids.
The formula of an area of a trapezoid:
[tex]A=\dfrac{base_1+base_2}{2}\cdot\ height[/tex]
We have:
[tex]base_1=210\ mm\\\\base_2=150\ mm\\\\height=55\ mm[/tex]
Substitute:
[tex]A=\dfrac{210+150}{2}\cdot55=\dfrac{360}{2}\cdot55=180\cdot55=9,900\ mm^2[/tex]
Answer:
[tex]2A=2\cdot9,900\ mm^2=19,800\ mm^2[/tex]
