Wallpaper was applied to one rectangular wall of a large room. the dimensions of the wall is 42 feet on one side and the other side 25.5 feet. if the total cost of the wallpaper was $771.12, what was the cost, in dollars, of the wallpaper per square foot?
plz !

.72¢ per square foot. 
In order to find this answer, first you need to find out how many square feet the wall is. Multiply the dimensions ( 42 x2 5.5), and that would give you the answer. (1,071). Now that we have the total square footage, you can cross multiply to find out how much 1 square foot would cost.    1,071       1
                                                                                          –––––– x ––––
                                                                                           771.12.      ?
Cross multiply to get the answer .72