find the centroid of the region bounded by the line y4 and t

find the centroid of the region bounded by the line y=4 and the graph of f(x)=x^2

integral from 0 to a of sqrt(x) = integral from a to 4 of sqrt(x)
2/3*x^3/2 from 0 to a = 2/3*x^3/2 from a to 4
2/3*a^3/2 = 16/3-2/3*a^3/2
4/3*a^3/2=16/3
a^(3/2)=4
a=4^(2/3)=2.52
(0,2.52) since it is centered around x=0