The constant of proportionality, often represented by 'k,' is the ratio of two quantities and represents their direct relationship.
In this case, we need to find the constant of proportionality 'k' that relates 'y' (the cost in dollars for apples) to 'x' (the number of pounds of apples).
To find 'k,' we divide 'y' by 'x.' Here, y represents the cost which is $10.24 and x represents the number of pounds which is 4.
So, using the formula 'k = y/x' to find the cost per pound of apples, we substitute 'y' with 10.24 and 'x' with 4:
=> k = 10.24 / 4
When we compute this division, we find that k = 2.56.
Therefore, the constant of proportionality that relates the cost in dollars to the number of pounds of apples is $2.56 per pound of apples.