Let d be a region bounded by a simple closed path c in the xy-plane. the coordinates of the centroid ( , ) of d are given below, where a is the area of d. = 1/2a x 2 dy = -1/2a y 2 dx use the formulas to find the centroid of the triangle with vertices (0, 0), (a, 0), and (a, b), where a > 0 and b > 0. {x, y) = ( )