We know there are 12'' in a foot, because we are converting from inches to feet we multiply by our conversion factor of 1ft/12" to get the carpet dimensions in feet. (This is the same as dividing by 12)
40"(1ft/12") = (40/12) ft
26'(1ft/12") = (26/12) ft
we can now find the square footage of the carpet by multiplying the length by width
40/12 ft * 26/12 = X square feet (preform the calculations to find the value of X)
finally multiply the number of square feet of carpet by the price per square foot to get the total price
X sq ft * $1.69/sq ft = Total price for carpet in dollars (plug the value of X into this equation and calculate price)