To find the ratio of shaded parts to unshaded parts, we can start by looking at the information provided:
- There are 4 shaded rectangles.
- There are 2 unshaded rectangles.
Now, we can express the ratio of shaded parts to unshaded parts:
\[ \text{Ratio of shaded to unshaded} = \frac{\text{Number of shaded rectangles}}{\text{Number of unshaded rectangles}} = \frac{4}{2} \]
To simplify this ratio:
\[ \frac{4}{2} = 2 \]
So, the ratio of shaded parts to unshaded parts is 2:1.
Now let's check if this matches any provided options:
- 2 shaded for every 4 unshaded: This is a ratio of 2:4, which simplifies to 1:2, not a match.
- 6 shaded for every 2 unshaded: This implies a ratio of 6:2, which simplifies to 3:1, not a match.
- 2 shaded for every 2 unshaded: This implies a ratio of 2:2, which simplifies to 1:1, not a match.
- 4 shaded for every 2 unshaded: This implies a ratio of 4:2, which simplifies to 2:1, this is a match.
Thus, the correct answer is 4 shaded for every 2 unshaded, which corresponds to a ratio of 2:1.