Finding the Fraction: What Portion Does the Blue Shaded Area Represent in a Grid Diagram

To solve this problem, we will determine how much of the whole grid is represented by the shaded area.

The problem provides a 10x10 grid which contains 100 smaller squares in total. Our task is to determine how many of these squares are shaded.

Upon inspection, we count that 80 out of the 100 squares are shaded.

Therefore, the fraction of the whole that the shaded area represents is given by dividing the number of shaded squares by the total number of squares:

$\frac{\text{shaded squares}}{\text{total squares}} = \frac{8}{10}$

Converting this fraction to a decimal gives $0.8$.

Thus, the shaded area represents $\frac{8}{10}$ or $0.8$ of the whole.

Among the choices provided, the correct answer is: $0.8$ or $\frac{8}{10}$.