Answer:
0.267 square units (or 8/30 square units)
Step-by-step explanation:
width = 3 rectangles
length = 10 rectangles (left to right)
area = width * length = 30 rectangles
the striped rectangle is made up of 8 regular rectangles
thus, (area we want) / (total area) = 8/30 of the whole ≈ 0.267 of the whole
the whole is 1 square unit, so 0.267 of 1 square unit = 0.267 * 1 square unit = 0.267 square units