Hey i suck at math can someone help me with this question

we can subtract the trapezium (white part) formed after from the trapezium (including white and grey) to get area of striped part

area of trapezium is where $a$ and $b$ are parallel sides.

for bigger trapezium, $h=4$ parallel sides are $5$ and $5$

hence area is $\frac{4(5+5)}{2}=20$

similarily area of white trapezium, $\frac{4(3+3)}{2}=12$

and area of striped part is $20-12=8$