For this case, the first thing to do is find the area of the trapezoid.
 We have then: 

 Where,
 b1: b2: Trapezoid bases
 h: height of the trapezoid
 Substituting values we have: 

 Then, the cost per square foot is given by: 
 Answer:
 The new carpet for the room will cost:
 C = 1072.5 $