The table shows the total cost of different numbers of square feet of carpet. What is the rate of change of the total cost in dollars with respect to the number of square feet purchased for this linear relationship?
Number of Square Feet Purchased
120
140
160
180
Total Cost (dollars)
840
980
1,120
1,260
To find the rate of change of the total cost in dollars with respect to the number of square feet purchased, we can calculate the slope of the line passing through the points (120, 840) and (180, 1260).
The formula for calculating slope is: slope = (change in y)/(change in x)
slope = (1260 - 840)/(180 - 120)
slope = 420/60
slope = 7
Therefore, the rate of change of the total cost in dollars with respect to the number of square feet purchased is $7 per square foot.