The figure is a trapezoid. The area of it is given by the formula ...
A = (1/2)(b1 +b2)h
where b1 and b2 are the lengths of the parallel bases and h is the distance between them.
Your figure shows the base lengths to be 5 and 3, and their separation to be 2. Filling the numbers in the formula, we have ...
A = (1/2)(5 +3)(2) = (1/2)(8)(2) = 4·2 = 8
The area of the figure is 8 square units.
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The right-pointing arrows on the horizontal lines identify those lines as being parallel. The right-angle indicator and the 2 next to the dotted line indicate the perpendicular distance between the parallel lines is 2 units.