The number of skeins of yarn is in the x-axis, and the number of hats is in the y-axis.
If Greta bought 5 skeins of yarn, let's find the value x = 5 in the graph.
Then, looking for the corresponding value of y in the line, we have y = 6.
This means Greta can knit a total of 6 hats using the 5 skeins of yarn she bought.