Use the formula for the centroid:
x ¯ = 1 A ∫ a b x ( f ( x ) − g ( x ) ) d x , and y ¯ = 1 2 A ∫ a b [ f ( x ) ] 2 − [ g ( x ) ] 2 d x {\displaystyle {\begin{aligned}{\bar {x}}={\frac {1}{A}}\int _{a}^{b}x(f(x)-g(x))dx,\quad {\text{and}}\quad {\bar {y}}={\frac {1}{2A}}\int _{a}^{b}[f(x)]^{2}-[g(x)]^{2}dx\end{aligned}}}
where A {\displaystyle A} is the area of the region.