An architectural drawing lists the scale as 1/4"=1'. if a bedroom measures 2 1/2" by 3 3/4" on the drawing, how large is the bedroom?

One way to solve this type of problem is to use proportions.

1/4"    equals 1 ft
2 1/4"  corresponds to how many feet?  Call this "x."

Then    1
            --
             4               1 ft
=
             9
            ---                 x
             4

Solve this for x.  First, reduce the first set of fractions.  That boils down to (1/9).  

Equate (1/9) to 1/x.  It's obvious that x = 9 (feet).

Use the same method to find the length of the bedroom.

Im sorry but what on

paul's with a y-intercept of $ 2856