You should first try to find the area of the entire rectangle.
Remember, the area of something is the total of the one unit squares that fit inside of a shape.
Do you remember the two ways to find the area of something?

If the square has $16$ squares inside of it, and the shaded portion is just one square, can you determine the shaded area?

The shaded area is $\frac{1}{16}$.

Can you think of multiple ways to represent this?

Gilly said that this area is the same as the length times the width of the portion $\left(\frac{1}{4} \cdot \frac{1}{4}\right)$.