To determine the relationship between the number of stitches and the length, we can look for a consistent factor that relates the two values based on the given data:
- For 7 stitches, length = 1 cm: \( 7 = 7 \times 1 \)
- For 21 stitches, length = 3 cm: \( 21 = 7 \times 3 \)
- For 28 stitches, length = 4 cm: \( 28 = 7 \times 4 \)
- For 42 stitches, length = 6 cm: \( 42 = 7 \times 6 \)
From this, we can see that the number of stitches is consistently 7 times the length in cm. So the correct relationship is:
The number of stitches is 7 times the length.