math
posted by kaykay on .
Susan has 50 ft. of fencing in her backyard. What is the largest area garden Susan can create, show the gardens dimensions and explain how you know its the largest area


Considering all rectangles with the same perimeter, the square encloses the greatest area.
Proof: Consider a square of dimensions x by x, the area of which is x^2. Adjusting the dimensions by adding a to one side and subtracting a from the other side results in an area of (x + a)(x  a) = x^2  a^2. Thus, however small the dimension "a" is, the area of the modified rectangle is always less than the square of area x^2. 
20x15