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Radius & Length of Red Arc.

Shaded Fraction = 1 / 2 = 0.5

Yellow + Orange = 25

Easy Way

Radius R = 1.85786437627

R₃ : R₂ : R₁ = 5 : 10 : 15

R Minor = 0.231446810027

sin X = sin BAC = 1 / 3

Alternative Solution

Angle ABC = X = 45 °

EP = 2.65165042945

Green Area = ( 5 S 𝜋 / 8 ) - S