In order to determine the are of the garden, use the formula for the are of a circular region (because Madison has a round garden), given by:
A = πr²
where r is the radius of the circle. Consider that the diameter of the garden is 14 feet. The radius is one half the diameter, then, the radius is r=14 ft/2 = 7 ft.
Replace the values of r = 7 ft and π = 3.14 in the formula for the area:
A = πr² = (3.14)(7 ft)²
A = 153.86 ft²
Hence, the area of the garden is 153.86 ft²