Given that :
Area of a rectangle is : A = l×b
For smaller garden,
Length, l =

Width,

Area of a smaller garden is :

For larger garden,
length, l' = 4 feet
Width, b' = 5 feet
Area of a larger garden is :

So, the area of a smaller garden is 0.34 sq ft and that of a larger garden is 20 sq ft.