A Rectangular $450 \mathrm{ft}^{2}$ Family Room Addition Is to Be Built Using the Existing

Multiple Choice

A rectangular, $450 \mathrm{ft}^{2}$ family room addition is to be built using the existing house for one of its walls. Find a function $\mathrm{f}(\mathrm{x})$ that would represent the total length of the other 3 walls that need to be built, where $x$ represents the length of the wall that will be parallel to the existing wall.

A) $f(x) =2 x+\frac{900}{x}$
B) $f(x) =x+\frac{450}{x}$
C) $f(x) =x+\frac{900}{x}$
D) $f(x) =3 x-\frac{450}{x}$