Venita is sewing new curtains. The table below shows the relationship between the number of stitches in a row and the length of the row.

Number of Stitches Length (cm)
7 1
21 3
28 4
42 6
What is the relationship between the number of stitches and the length?

1 answer

To understand the relationship between the number of stitches and the length of the row, let's first organize the data:

  • When there are 7 stitches, the length is 1 cm.
  • When there are 21 stitches, the length is 3 cm.
  • When there are 28 stitches, the length is 4 cm.
  • When there are 42 stitches, the length is 6 cm.

Now, let's examine the data to identify a pattern.

  1. Calculate the stitches per cm:
    • For 1 cm: \( \frac{7 \text{ stitches}}{1 \text{ cm}} = 7 \text{ stitches/cm} \)
    • For 3 cm: \( \frac{21 \text{ stitches}}{3 \text{ cm}} = 7 \text{ stitches/cm} \)
    • For 4 cm: \( \frac{28 \text{ stitches}}{4 \text{ cm}} = 7 \text{ stitches/cm} \)
    • For 6 cm: \( \frac{42 \text{ stitches}}{6 \text{ cm}} = 7 \text{ stitches/cm} \)

The number of stitches per cm is consistent at 7 stitches for each row length.

  1. Create an equation for the relationship: Given that the relationship between the number of stitches (S) and the length (L) can be expressed as:

    \[ S = 7L \]

This equation indicates that the number of stitches is directly proportional to the length of the row, with a constant of proportionality equal to 7.

Conclusion: The relationship between the number of stitches and the length of the row is linear, represented by the equation \( S = 7L \), indicating that for every centimeter of length, there are 7 stitches.