Problems 53-58, set up a definite integral that represents the area bounded by the graphs of the indicated equations over the given interval. Find the areas to three decimal places. [Hint: A circle of radius r, with center at the origin, has equation x2 + y2 = r2 and area πr2]
y = - √36 - x2; y = 0; - 6 ≤ x ≤ 0