Use the formulas for the centroid
x ¯ = 1 A ∫ a b x ( f ( x ) − g ( x ) ) d x {\displaystyle {\bar {x}}={\frac {1}{A}}\int _{a}^{b}x(f(x)-g(x))dx}
y ¯ = 1 A ∫ a b f ( x ) + g ( x ) ) 2 ( f ( x ) − g ( x ) ) d x {\displaystyle {\bar {y}}={\frac {1}{A}}\int _{a}^{b}{\frac {f(x)+g(x))}{2}}(f(x)-g(x))dx}
with the appropriate choice of f ( x ) , g ( x ) , a , b {\displaystyle f(x),g(x),a,b} .
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